For the two?dimensional Planar Frequency Diverse Array(PFDA) radar, in the process of suppressing the interference which is close to the target in angle dimension and separable in range dimension, the classic beamforming algorithm has the problem of mainlobe distortion when the steering vector is mismatched. Based on the cross ?subarray two ?dimensional planar frequency diverse array with sine offset, this paper uses the variable load constraint with the fastest descent linear constraint minimum variance criterion to solve the correction weight vector when the steering vector is mismatched. When the estimated steering vector is 2°, it can still achieve effective correction and shape?preserving of the mainlobe when the pointing error is high. The simulation verifies the effectiveness of the method in this paper.