Aiming at the requirements of millimeter and sub millimeter wave radiometer for quasi optical feed network, a 23~425 GHz ten channels quasi optical feed network is designed by GRASP software, using flat plane to achieve a double layers quasi optical feed network and reduce the size,using polarization grids and Frequency Selective Surfaces(FSS) to separate different channels. Through simulating the specifications of each channel, the test results are consistent with the simulation results.