diff --git a/UI/DrawingParamsForm.cs b/UI/DrawingParamsForm.cs
index 8f1305d..e2d1150 100644
--- a/UI/DrawingParamsForm.cs
+++ b/UI/DrawingParamsForm.cs
@@ -23,6 +23,15 @@ namespace CadParamPluging.UI
         private readonly RichTextBox _rtbNoteRendered;
         private Dictionary<int, NoteTemplateEngine.PlaceholderOccurrence> _occByIndex;
 
+        // 最小壁厚T自动计算相关
+        private bool _canAutoCalcMinWallThickness;
+        private Control _ctrlMinWallThickness;
+        private const string KeyOuterDiameter1 = "OuterDiameter1";
+        private const string KeyOuterDiameter1TolMinus = "OuterDiameter1TolMinus";
+        private const string KeyInnerDiameter2 = "InnerDiameter2";
+        private const string KeyInnerDiameter2TolPlus = "InnerDiameter2TolPlus";
+        private const string KeyMinWallThickness = "MinWallThickness";
+
         public ParamBag Result { get; private set; }
 
         public DrawingParamsForm(ParamCatalog catalog, TemplateSchemaDefinition schema)
@@ -130,6 +139,7 @@ namespace CadParamPluging.UI
                 split.Panel2MinSize = 280;
                 EnsureValidSplitterDistance(split);
                 UpdateNotePreviews();
+                CheckMinWallThicknessAutoCalc();
             };
         }
 
@@ -385,6 +395,7 @@ namespace CadParamPluging.UI
             _defsByControlKey[controlKey] = def;
 
             AttachPreviewUpdate(ctrl);
+            AttachMinWallThicknessUpdate(controlKey, ctrl);
         }
 
         private void AttachPreviewUpdate(Control ctrl)
@@ -419,6 +430,137 @@ namespace CadParamPluging.UI
             }
         }
 
+        private void AttachMinWallThicknessUpdate(string paramKey, Control ctrl)
+        {
+            if (ctrl == null || string.IsNullOrWhiteSpace(paramKey))
+            {
+                return;
+            }
+
+            var key = paramKey.Trim();
+            if (!string.Equals(key, KeyOuterDiameter1, StringComparison.OrdinalIgnoreCase)
+                && !string.Equals(key, KeyOuterDiameter1TolMinus, StringComparison.OrdinalIgnoreCase)
+                && !string.Equals(key, KeyInnerDiameter2, StringComparison.OrdinalIgnoreCase)
+                && !string.Equals(key, KeyInnerDiameter2TolPlus, StringComparison.OrdinalIgnoreCase))
+            {
+                return;
+            }
+
+            if (ctrl is NumericUpDown num)
+            {
+                num.ValueChanged += (_, __) => UpdateMinWallThickness();
+            }
+            else if (ctrl is TextBox tb)
+            {
+                tb.TextChanged += (_, __) => UpdateMinWallThickness();
+            }
+        }
+
+        private void CheckMinWallThicknessAutoCalc()
+        {
+            _canAutoCalcMinWallThickness = false;
+
+            if (!_controlsByKey.ContainsKey(KeyMinWallThickness))
+            {
+                return;
+            }
+
+            _ctrlMinWallThickness = _controlsByKey[KeyMinWallThickness];
+
+            var hasOuter = _controlsByKey.ContainsKey(KeyOuterDiameter1);
+            var hasOuterTol = _controlsByKey.ContainsKey(KeyOuterDiameter1TolMinus);
+            var hasInner = _controlsByKey.ContainsKey(KeyInnerDiameter2);
+            var hasInnerTol = _controlsByKey.ContainsKey(KeyInnerDiameter2TolPlus);
+
+            if (hasOuter && hasOuterTol && hasInner && hasInnerTol)
+            {
+                _canAutoCalcMinWallThickness = true;
+                UpdateMinWallThickness();
+
+                if (_ctrlMinWallThickness != null)
+                {
+                    _toolTip.SetToolTip(_ctrlMinWallThickness, "自动计算: T=(Φ1-b1+Φ2-a2)/2\n(根据外径Φ1、外径下差b1、内径Φ2、内径上差a2)");
+                }
+            }
+            else
+            {
+                var missing = new List<string>();
+                if (!hasOuter) missing.Add("外径Φ1");
+                if (!hasOuterTol) missing.Add("外径下差b1");
+                if (!hasInner) missing.Add("内径Φ2");
+                if (!hasInnerTol) missing.Add("内径上差a2");
+
+                if (_ctrlMinWallThickness != null && missing.Count > 0)
+                {
+                    var msg = string.Format("需人工填写（缺少参数: {0}）", string.Join(", ", missing));
+                    _toolTip.SetToolTip(_ctrlMinWallThickness, msg);
+                }
+            }
+        }
+
+        private void UpdateMinWallThickness()
+        {
+            if (!_canAutoCalcMinWallThickness || _ctrlMinWallThickness == null)
+            {
+                return;
+            }
+
+            try
+            {
+                var phi1 = GetNumericValue(KeyOuterDiameter1);
+                var b1 = GetNumericValue(KeyOuterDiameter1TolMinus);
+                var phi2 = GetNumericValue(KeyInnerDiameter2);
+                var a2 = GetNumericValue(KeyInnerDiameter2TolPlus);
+
+                // T = (Φ1 - b1 + Φ2 - a2) / 2
+                // 注意：b1通常为负数（如-0.5），a2通常为正数（如0.5）
+                // 实际最小壁厚 = ((外径最小) - (内径最大)) / 2
+                // 外径最小 = Φ1 + b1，内径最大 = Φ2 + a2
+                // 最小壁厚 = (Φ1 + b1 - Φ2 - a2) / 2
+                // 但用户公式为 T=(Φ1-b1+Φ2-a2)/2，按此公式计算
+                var t = (phi1 - b1 + phi2 - a2) / 2.0;
+
+                if (_ctrlMinWallThickness is NumericUpDown num)
+                {
+                    var val = (decimal)t;
+                    if (val < num.Minimum) val = num.Minimum;
+                    if (val > num.Maximum) val = num.Maximum;
+                    num.Value = val;
+                }
+            }
+            catch
+            {
+                // ignore calculation errors
+            }
+        }
+
+        private double GetNumericValue(string key)
+        {
+            if (!_controlsByKey.TryGetValue(key, out var ctrl) || ctrl == null)
+            {
+                return 0;
+            }
+
+            if (ctrl is NumericUpDown num)
+            {
+                return (double)num.Value;
+            }
+
+            if (ctrl is TextBox tb)
+            {
+                if (double.TryParse(tb.Text, NumberStyles.Float, CultureInfo.InvariantCulture, out var v))
+                {
+                    return v;
+                }
+                if (double.TryParse(tb.Text, NumberStyles.Float, CultureInfo.CurrentCulture, out v))
+                {
+                    return v;
+                }
+            }
+
+            return 0;
+        }
+
         private void UpdateNotePreviews()
         {
             if (_schema == null)