The invention discloses an active power control method for a flexible distribution network power supply system. n flexible converters, n distribution transformers, n sections of alternating current buses and one direct current bus are arranged in the flexible distribution network power supply system, the two ends of each flexible converter are connected with one ends of the direct current bus andthe corresponding alternating current bus respectively, and the other end of each alternating current bus is connected with the corresponding distribution transformer, wherein n is an integer, and n is greater than or equal to 2; any one flexible converter operates in a direct current bus voltage control mode, the other flexible converters operate in an active and reactive power control mode, andwhen any alternating current bus is overloaded, a coordination control unit controls one or more flexible converters to realize active power support on the overloaded alternating current bus, so thatoverload of the distribution transformer is prevented. According to the method, the load condition of each bus can be monitored in real time, a flexible converter power instruction is obtained throughtraditional proportional integral control, power flow between the buses is coordinated automatically and flexibly, and overload of a distribution transformer is prevented; the control scheme is simple and easy for engineering realization.