In order to meet the need of laser frequency shift and precision sweep in cold atom interferometry experiments, a control system for acousto-optic modulator with digital interface was designed and implemented. The control system consists of three components, namely upper computer (PC), microcontroller (ARM) and radio-frequency generator (DDS). Among them, PC is used to collect control information. ARM chip controls the DDS chip according to control information, so that the DDS chip can generate a RF driving signal for acousto-optic modulator, and obtain the desired laser frequency for experiments. The control system can output RF signals with frequency of 0～150 MHz and phase noise as low as －116 dBc/Hz. Meanwhile, the amplitude, phase and frequency sweep rate and other parameters of the output signals can be controlled efficiently. Additionally it offers a variety of operating modes to meet different requirements in cold atom interferometry experiments.