fpga is configured successfully but cannot work

Are you sure you have both FPGA images in your .jic or .pof files (and in the correct order if your FPGAs are different)? If you're using a .jic, you have to be sure the other FPGA is configured (and configured first) because the .jic does two things -- first configures the FPGA (only one) with an image that allows access from the JTAG chain to the EPCS device, then downloads the config file to the EPCS device through the FPGA. If the other FPGA in the chain isn't configured, it's possible that the first step won't complete because the FPGA won't wake up (most likely if CONF_DONE signals are tied together).

Assuming there's no problems with the schematic, using AS programming is probably the better method for writing the EPCS device in your case. Make sure both FPGA images are in the .pof file. And make sure you cycle power on the board after programming so the FPGAs load from EPCS.

It sounds like a basic configuration problem.