A low RCS (radar cross section) 2×2 OAM (orbital angular momentum) array antenna is designed based on the phase controlling metasurface.The array antenna is composed of four aperture coupled micro\|strip antennas, and a feeding network with same amplitude and the phase values of 0°, 90°, 180°, and 270° for different ports, realizing the OAM radiation effect of mode 1. According to the principle of phase cancellation to reduce RCS, a meta\|surface is constructed based on two units of artificial magnetic conductor with around the array antenna being loaded in the form of a checkerboard array, realizing effective reduction of antenna RCS. The simulated results show that the operating bandwidth of the array antenna is from 4.22 GHz to 5.16 GHz, and the gain is 8.91 dBi. The array antenna achieves the reduction of 8 dB RCS from 5.3 GHz to 7.0 GHz, and the reduction of 10 dB RCS from 5.35 GHz to 6.05 GHz.