Regarding the liquid crystal phased array component of radar, how to select a certain amount scanning angles so as to satisfy the conditions that the light-beams of all scanning angles can cover the field of view and meet the scanning index is a brand-new problem. This paper proposes a method of scanning angles screening based on the beam-steering model of binary grating. In the method, the scanning angles are obtained by using a traversal algorithm. The beamsteering model of binary grating is used to steer the light beam and the uniform coverage of the field of view, maximum sidelobe level, diffraction efficiency are regarded as constraint conditions of scanning angles screening. The simulation results from Matlab show that the method is effective and feasible.