Jianwen,
This looks like the
TxRxBlinky example. However you added delays which as TomWS noted - will cripple everything.
Please spend a little time to look at the code and try to understand what it does. Then load it to your Motes. This is the same sketch for both the sender and receiver. Set the parameters of the RFM radio to match your hardware (frequency, HCW or not, different node IDs, same network ID).
The examples in the library are guaranteed to WORK.
If you have no experience with these modules,
always start from a working example then make your changes gradually. If the example does not work, then you are doing something wrong, either some code setting, or hardware wiring, so circle back and verify everything is OK before trying again. Once the example works, then you are ready for changes.
Good luck.