沒寫過vba, 臨時改了一下，測試過可下載，參考Daniel意見

下載函數

Sub download(str As String)
    Dim myURL As String

    '來源檔案
    myURL = "http://download.post.gov.tw/post/download/Village_H_1" & str & ".xls"

    Dim WinHttpReq As Object
    Set WinHttpReq = CreateObject("Microsoft.XMLHTTP")
    WinHttpReq.Open "GET", myURL, False
    WinHttpReq.Send

    myURL = WinHttpReq.ResponseBody
    If WinHttpReq.Status = 200 Then
        Set oStream = CreateObject("ADODB.Stream")
        oStream.Open
        oStream.Type = 1
        oStream.Write WinHttpReq.ResponseBody

       '儲存檔案位置
        oStream.SaveToFile ("d:\Village_H_1" & str & ".xls")
        oStream.Close
    End If
End Sub

執行函數

Sub exec()
    Dim i, j As Integer
    Dim d, h, str As String
    For i = 1 To 12
        d = Format(i, "00")
        For j = 1 To 23
           h = Format(j, "00")
           str = d & h
           download str
        Next
    Next i
End Sub