Aiming at the problem that the number of modular multi-level converter sub-modules is large and the traditional full-order operation is large, a new strategy of MMC equalization optimization based on heap sorting algorithm is proposed. Through the theoretical analysis of the heap sorting, the mathematical formula of time complexity is deduced. When the number of sub-modules is larger, the number of comparison sequences can be reduced by more than 60% compared with traditional sequencing, and the sorting rate is optimized; In addition, in order to simplify the complexity of the control system, combined with improved carrier modulation strategy, the use of shared Modulation Wave on the sub-module capacitor voltage modulation, improved voltage equalization effect. Simulation and analysis of the modular multi-level converter model were carried out by Matlab / Simulink to verify the effectiveness of the equalization optimization strategy based on the heap sorting algorithm and the improved carrier modulation; While the voltage equalization effect is maintained, the heap ordering algorithm effectively solves the problem of large computation compared with the traditional full sorting algorithm.