In this paper, a 256level linear acoustooptic modulation driving source with diffracted optical power linearly varying with gray level is designed. The design uses a digital voltage control circuit with a digital potentiometer DS3902 as the core to generate a digital voltage with 256 levels in the input voltage of the acoustooptic modulator from 0 to 5 V, and the performance of the acoustooptic modulator is investigated. According to the inherent nonlinear characteristics of the acoustooptic device, the linear correlation coefficient between the compensated diffracted optical power and the gray level can reach 99.91%, which is 1.15% higher than that before compensation.