In train traction inverter, to prevent simultaneous breakover of the up and down switches, dead time should be added in the turnon time of the switch. The fifth and seventh current harmonics would be produced by permanent magnet synchronous motor (PMSM). Obviously, it was necessary to study the suppression of harmonics. Firstly, the fifth and seventh harmonics caused by dead time were analyzed. Secondly, the adaptive notch filter was used to extract the harmonic components of the current to compensate the dead time, and the stability was analyzed. Finally, the effectiveness of the proposed method was verified on the MATLAB/Simulink platform.