昨天就是你问的吧?
Private Sub Command1_Click()
Dim a(4) As String
a(1) = "a"
a(2) = "b"
a(3) = "c"
a(4) = "d"
For i = 1 To 4
For j = 1 To 4
For x = 1 To 4
For y = 1 To 4
If i <> j And i <> x And i <> y And j <> x And j <> y And x <> y Then Print a(i) & a(j) & a(x) & a(y)
Next y
Next x
Next j
Next i
End Sub