A two-dimensional phase gradient meta-surface based on cross structure insensitive to polarization is designed and verified by simulation and experiment. Several periodic metal cross structures are integrated into a superstructure, and an additional component of the wave vector on the meta-surface is formed and the direction of refelction wave can be regulated. Thus the backward radar cross section (RCS) reduction can be realized by the mechanism of anomalous reflection. Experimental results indicate that in a frequency range from 3.2 to 3.4 GHz, the reduction of backward RCS of meta-surface reaches a highest value of 18.19 dB in the normal direction of meta-surface and 8 dB on the average in an angular range between -30° and +30°.