The utilization of constant switching frequency pulse width modulation (CSFPWM) in the Vienna rectifier leads to the generation of numerous electromagnetic interference (EMI) spikes within its frequency spectrum. A sinusoidal spread spectrum modulation method is presented in this paper. When the maximum amplitude of three-phase current increases, the switching frequency decreases. On the basis of reducing EMI, the efficiency of the system is improved by reducing the switching loss. The experimental results show that compared with CSFPWM, sinusoidal PWM (SINPWM) can reduce the conducted EMI by 15 dB.