Firstly, an electronically controlled 1-bit coding unit covering S-band is designed, and its equivalent circuit analysis and parameter optimization are carried out. The phase difference of the unit is 180° under two working states of 0/1; On this basis, the design of 9×9 metasurface array is completed. By adjusting the bias voltage at both ends of varactor, the working state of each unit is changed to eliminate the interference of reflected electromagnetic wave energy. The simulation results show that the coded metasurface designed in this paper can achieve RCS reduction of more than 15 dB compared with the metal plate of the same size in the range of 2 GHz~4 GHz.