Abstract: When modular multilevel converter（MMC）is used in high voltage direct current（HVDC）system,PI control method is usually adopted,but this strategy has the disadvantages of complex parameter selection and poor dynamic performance. In order to improve the dynamic performance of the system and simplify the selection of parameters,this paper proposes a Lyapunov control strategy for the back-to-back（B2B）MMC-HVDC system. Firstly,the mathematical model of B2B MMC-HVDC is established;Secondly,the Lyapunov function control strategy is designed. Next,the circulating current suppression and phase-shift carrier modulation are added in the control part to realize the system function completely. Finally,the Lyapunov control strategy is verified to have the characteristics of easy parameter selection and excellent dynamic performance on Matlab/Simulink platform.