Abstract: To solve the three-phrase unbalanced operation of coal mine power supply system, a power balance control strategy of D-STATCOM was proposed.It proposed a D-STATCOM system connection diagram and analyzed the effects of power asymmetry on the D-STATCOM control characteristics.To realize theP-Q independent control of active power and reactive power, it mentioned a single-phase power decoupling control method.Through zero sequence voltage injection, it advanced a kind of energy conversion mechanism between zero sequence and active power.Matlab/Simulink simulation results show that during the three-phrase unbalanced operation of coal mine power supply system, not only can the D-STATCOM control the reactive power independently, but also balance the three-phase active current operation.