Proposed a random zero vector ratio modulation method to suppress electric vehicle inverter electromagnetic interference. The method based on the original segment symmetrical modulation method randomly changed the ratio between the two zero vectors to realize random modulation; Used the Matlab / Simulink software to build a permanent magnet synchronous motor vector control simulation model; Applied a certain type of electric vehicle motor drive system for the algorithm experimental analysis. Simulation results show that comparing with seven segment symmertry, the random zero vector ratio modulation can reduce harmonic amplitude of carrier frequency and carrier times frequency, thereby reducing conducted EMI.