Quantization digit of voltage limits the choice scope of wave front phase, causes actual angle deviating from ideal angle, and further decreases steering accuracy. Steering accuracy is one of the most significant performance indexes of liquid-crystal phased array (LCPA). An optimization algorithm is proposed aiming at improving steering accuracy. The algorithm is based on optimization theory; it adopts method of pattern search to optimize objective using the way of adjusting voltage staircase. The influence of voltage quantization on steering accuracy is analyzed first, and then model of wave control is established. Last the decreasing of deviations between actual angle and ideal angle is taken as objective to correct corresponding voltage staircases using pattern search. Simulation results show that the algorithm can decrease normalized accuracy error from order of 100 to 10-3 in the range of scanning angles, which is remarkable.