到这段弹确认或取消对话框，但不关选哪个最后执行的是同样的结果

你得把删除的代码放到确认删除的后面：

Private Sub 删除物料_Click()
On Error GoTo Err_删除物料_Click
Dim STemp As String
Dim i As Integer
Dim Rs As ADODB.Recordset
Set Rs = New ADODB.Recordset
STemp = "Select * From [tbl_ 车加工出库]"
Rs.Open STemp, CurrentProject.Connection, adOpenKeyset, adLockOptimistic
    Rs.MoveFirst
    For i = 1 To Rs.RecordCount
        If Rs("lsbh") = Me![frm_ 车加工出库_child]![lsbh] Then
          If MsgBox("您确认要删除！", vbOKCancel + vbInformation, "提示：") = vbOK Then'确认删除
            Rs.Delete 1
            i = Rs.RecordCount + 1

          end if
        Else
            Rs.MoveNext
        End If
    Next i
    'If MsgBox("您确认要删除！", vbOKCancel + vbInformation, "提示：") = vbOK Then
    Me![frm_ 车加工出库_child].Requery
    Set Rs = Nothing
Exit_删除物料_Click:
    Exit Sub
Err_删除物料_Click:
    MsgBox Err.Description
    Resume Exit_删除物料_Click
    End If
End Sub

试一下