diff --git a/src/value/convert/convert.ts b/src/value/convert/convert.ts
index 5342320ed..cddb0cf22 100644
--- a/src/value/convert/convert.ts
+++ b/src/value/convert/convert.ts
@@ -119,7 +119,8 @@ function TryConvertBoolean(value: unknown) {
   return IsValueTrue(value) ? true : IsValueFalse(value) ? false : value
 }
 function TryConvertBigInt(value: unknown) {
-  return IsStringNumeric(value) ? BigInt(parseInt(value)) : IsNumber(value) ? BigInt(value | 0) : IsValueFalse(value) ? BigInt(0) : IsValueTrue(value) ? BigInt(1) : value
+  const truncateInteger = (value: string) => value.split('.')[0];
+  return IsStringNumeric(value) ? BigInt(truncateInteger(value)) : IsNumber(value) ? BigInt(value | 0) : IsValueFalse(value) ? BigInt(0) : IsValueTrue(value) ? BigInt(1) : value
 }
 function TryConvertString(value: unknown) {
   return IsValueToString(value) ? value.toString() : IsSymbol(value) && value.description !== undefined ? value.description.toString() : value
diff --git a/test/runtime/value/convert/bigint.ts b/test/runtime/value/convert/bigint.ts
index c5057ab00..350e7a1f4 100644
--- a/test/runtime/value/convert/bigint.ts
+++ b/test/runtime/value/convert/bigint.ts
@@ -23,6 +23,26 @@ describe('value/convert/BigInt', () => {
     const R = Value.Convert(T, 'false')
     Assert.IsEqual(R, BigInt(0))
   })
+  it('Should convert bigint from string 5', () => {
+    const T = Type.BigInt()
+    const R = Value.Convert(T, '12345678901234567890')
+    Assert.IsEqual(R, BigInt("12345678901234567890"))
+  })
+  it('Should convert bigint from string 6', () => {
+    const T = Type.BigInt()
+    const R = Value.Convert(T, '-12345678901234567890')
+    Assert.IsEqual(R, BigInt("-12345678901234567890"))
+  })
+  it('Should convert bigint from string 7', () => {
+    const T = Type.BigInt()
+    const R = Value.Convert(T, '12345678901234567890.123')
+    Assert.IsEqual(R, BigInt("12345678901234567890"))
+  })
+  it('Should convert bigint from string 8', () => {
+    const T = Type.BigInt()
+    const R = Value.Convert(T, '-12345678901234567890.123')
+    Assert.IsEqual(R, BigInt("-12345678901234567890"))
+  })
   it('Should convert bitint from number 1', () => {
     const T = Type.BigInt()
     const R = Value.Convert(T, 1)