thank u，i got it work。
Sorry for late. I am busy for my new shop in suzhou.
After you install the kext, you need boot with -s and input fsck -f -y for repair disk permission, i got the same problem as you before fix disk permission, after that, i got it work.
snow leopard just recognized 5600series before i tried -s，and i input exit。Then，done（SAPPHIRE 5570）