diff --git a/web-admin/scripts/pl-freight-calc-reset.test.ts b/web-admin/scripts/pl-freight-calc-reset.test.ts
new file mode 100644
index 000000000..8300b8f03
--- /dev/null
+++ b/web-admin/scripts/pl-freight-calc-reset.test.ts
@@ -0,0 +1,91 @@
+import assert from 'node:assert/strict'
+import { existsSync, readFileSync } from 'node:fs'
+import test from 'node:test'
+import ts from 'typescript'
+import * as vue from 'vue'
+
+function loadFreightCalc() {
+  const path = new URL('../src/composables/usePlFreightCalc.ts', import.meta.url)
+  assert.ok(existsSync(path), 'usePlFreightCalc must exist')
+  const source = readFileSync(path, 'utf8')
+  const ast = ts.createSourceFile('usePlFreightCalc.ts', source, ts.ScriptTarget.Latest, true)
+  const code = ast.statements
+    .filter((node) => !ts.isImportDeclaration(node))
+    .map((node) => node.getText(ast))
+    .join('\n')
+  const compiled = ts.transpileModule(code, {
+    compilerOptions: { target: ts.ScriptTarget.ES2022, module: ts.ModuleKind.CommonJS }
+  }).outputText
+  const module = { exports: {} as Record<string, unknown> }
+  const requireStub = () => {
+    throw new Error('unexpected require in freight calc test harness')
+  }
+  // eslint-disable-next-line no-new-func
+  const factory = new Function(
+    'exports',
+    'require',
+    'module',
+    '__filename',
+    '__dirname',
+    'computed',
+    'ref',
+    'watch',
+    compiled + '\nmodule.exports = { usePlFreightCalc, sumProductActualQuantities };'
+  )
+  factory(
+    module.exports,
+    requireStub,
+    module,
+    'usePlFreightCalc.ts',
+    '.',
+    vue.computed,
+    vue.ref,
+    vue.watch
+  )
+  return module.exports as {
+    usePlFreightCalc: typeof import('../src/composables/usePlFreightCalc').usePlFreightCalc
+  }
+}
+
+test('resetFreightCalc re-sums transport qty from existing product actuals', async () => {
+  const { usePlFreightCalc } = loadFreightCalc()
+  const products = vue.ref([{ actualQty: 0.04, unit: '吨' }, { actualQty: 0.04, unit: '吨' }])
+  const hasFreight = vue.ref(1)
+  const freightType = vue.ref('by_weight')
+
+  const scope = vue.effectScope()
+  const calc = scope.run(() => usePlFreightCalc({ products, hasFreight, freightType }))
+  assert.ok(calc)
+  await vue.nextTick()
+  assert.equal(calc!.transportQty.value, 0.08)
+
+  calc!.resetFreightCalc()
+  await vue.nextTick()
+  assert.equal(calc!.transportQtyTouched.value, false)
+  assert.equal(
+    calc!.transportQty.value,
+    0.08,
+    'reset after products already loaded must not leave transport qty empty'
+  )
+  scope.stop()
+})
+
+test('resetFreightCalc restores product sum after manual transport qty edit', async () => {
+  const { usePlFreightCalc } = loadFreightCalc()
+  const products = vue.ref([{ actualQty: 0.04, unit: '吨' }])
+  const hasFreight = vue.ref(1)
+  const freightType = vue.ref('by_weight')
+
+  const scope = vue.effectScope()
+  const calc = scope.run(() => usePlFreightCalc({ products, hasFreight, freightType }))
+  assert.ok(calc)
+  await vue.nextTick()
+
+  calc!.transportQty.value = 9.9
+  calc!.markTransportQtyTouched()
+  calc!.resetFreightCalc()
+  await vue.nextTick()
+  assert.equal(calc!.transportQtyTouched.value, false)
+  assert.equal(calc!.transportQty.value, 0.04)
+  scope.stop()
+})
diff --git a/web-admin/src/composables/usePlFreightCalc.ts b/web-admin/src/composables/usePlFreightCalc.ts
index b30c9d724..91be7f256 100644
--- a/web-admin/src/composables/usePlFreightCalc.ts
+++ b/web-admin/src/composables/usePlFreightCalc.ts
@@ -86,11 +86,13 @@ export function usePlFreightCalc(options: {
   )
 
   function resetFreightCalc() {
-    transportQty.value = null
     transportQtyTouched.value = false
     freightAmount.value = null
     freightAmountTouched.value = false
     freightPrice.value = null
+    // 产品已加载时 watch 不会因 reset 重跑；须立即按当前实际数量回填，
+    // 否则归档弹窗再次打开会误报「运输量须大于0」。
+    transportQty.value = defaultTransportQty.value || null
   }
 
   function markTransportQtyTouched() {