In order to solve the output waveform of matrix converter (MC) under input voltage sag, this paper proposes a new control strategy for MC. The main function is according to the output voltage change real-time to modulation coefficient to compensation voltage fluctuations,and reduce the output harmonic. Finally under the input voltage sag condition application Matlab/Simulink to simulation. The results show that the optimization strategy is effectively to improve the quality of the output voltage and reduce the output harmonics.