Based on the principle of diffraction gratings, the beam scanning angle is calculated for the wavelength of 1 550 nm with the reflective liquid crystal optical phased array(LCOPA) as the research object. And the periodic and non-periodic scanning modes are simulated and analyzed. The phase diagram program and test software of periodic and non-periodic scanning modes are compiled. LCOPA is based on the theory of pure-phase modulation, which can achieve the real-time and programmable control for optical phase. The results show that the maximum detection distance is about 1.3 km when the defection angle is 2.4°. The test scanning system is of value in the fields of multi-object tracing, laser guiding and multi-object defense.