The invention discloses a vector control method for controlling the power of each DC port in a three-phase multi-port converter. The method comprises the following steps: giving a reference voltage vector and the target power of each port of the three-phase multi-port converter; decomposing the reference voltage vector into a voltage vector of each port according to the target power of each port;calculating the duty ratio of the voltage vector of each port on each phase according to the voltage vector of each port; when the sum of the duty ratios of the ports on each phase is less than or equal to 1, modulating and driving the power of each port according to the voltage vector of each port. According to the vector control method, the port power is controlled by controlling the port voltage vector, and power distribution and energy exchange between ports can be realized.