The invention discloses a power distribution method for multiple constant direct current voltage stations in a multi-terminal flexible direct current power transmission system. At least two conversion stations are constant direct current voltage stations controlled by using direct current voltage slope, and the rest conversion stations are constant power conversion stations controlled by using constant active power; the multi-terminal flexible direct current power transmission system is provided with n constant direct current voltage stations, m constant power conversion stations and a power distribution unit; the power distribution unit is provided with a power feedback calculation unit and n direct current voltage control units connected with the constant direct current voltage stations one to one; the power feedback calculation unit is provided with n filters and an adder; each direct current voltage control unit is provided with a distributor, a first comparator, a proportional integrator, a second comparator and a direct current voltage slope controller respectively; each constant direct current station is provided with a direct current voltage slope control unit, an outer ring voltage controller, an inner ring current controller, a reverse PARK converter and a converter valve. The system operation voltage is stabilized to rated voltage.