The invention relates to an electrical equipment local discharge positioning method and system. The method comprises the following steps of selecting one of a plurality of wireless sensors as a master clock and the other wireless sensors as slave clocks, and synchronizing the time of the master clock and the slave clocks; controlling the master clock to transmit a synchronous measurement instruction, and enabling the slave clocks to synchronously collecting ultrasonic signals generated in an electrical equipment measuring position at the same time with the master clock after receiving the synchronous measurement instruction; obtaining the head wave time of the ultrasonic signals in a wireless mode, which is recorded by a local discharge pulse time extracting module in every wireless sensor, selecting the shortest four head wave times, and according to the four head wave times and the positions of the corresponding wireless sensors determining the local discharge position of electrical equipment. By achieving ultrasonic collection and positioning through the wireless sensors, the electrical equipment local discharge positioning method is low in workload and high in safety.