Thanks very much!
Now,i know what's wrong with it.
The server is dell 1950, is x86_64, and the asm is 64 bit, but the oracle DB installer is 32bit.So, when i create db instance, it says lost contact or can't connect to oracle.
Finally,i try to install all of them with vnc, when oracle check os ,it warn the os is x86_64.
thanks very much