The invention discloses a self-positioning substation equipment electrified water washing robot system and method. A laser sensor is used for collecting practical position information of a working site insulator string, the information is used as main servo positioning data, data collected by a vision sensors and laser data are fused to serve as an auxiliary means for servo positioning, and accurate servo positioning of a water gun joint is achieved. Meanwhile, an inclination angle sensor is used for detecting the inclination angle of a robot in real time, a servo positioning instruction is corrected according to the angle information, and a water gun is driven to move to aim at the insulator string. By the adoption of full-automatic real-time monitoring, the fact that the water washing robot can correctly conduct self-positioning according to the posture of the robot as well as the distance and angle of the robot relative to the insulator string when the insulator string is washed canbe guaranteed, then self-adjustment is conducted, and automatic and accurate washing is achieved.