According to the disadvantages of the traditional three-level apace vector pulse width modulation (SVPWM) algorithm with a large amount of computation and poor real time, A simplified SVPWM algorithm based on rotation and unified processing of reference voltage is proposed, and it is applied to the three level indirect matrix converter (TLIMC). The method by judging the big sector of the output reference voltage and unify rotation to the first sector, then judge the small triangle area, and optimize the function time of the vector to reduce the amount of computation to the original 1/6, more suitable for digital signal processor program. Finally, the TLIMC simulation model of Matlab/Simulink is constructed, The simulation results prove the feasibility of the simplified method.