Abstract: Fire-fighting robot plays an important role in promoting the construction of unmanned substation and ensuring fire safety of substation.In order to ensure the extinguishing ability of the fire-fighting robot in substation,the robot should be provided with various kinds of fire extinguishing media,such as superfine powder,fire water and foam.The fire medium supply scheme of substation fire-fighting robot was designed.A standard dry powder tank was installed on the robot body to store ultra-fine dry powder,which was convenient for rapid replacement and improve efficiency.The scheme was equipped with firefighting medium supply equipment and docking with the robot through the water hose to provide stable and continuous fire foam and fire protection for the robot.Foam agent and fire water could be mixed and regulated by various proportions.The booster pump was used to realize the pressurization of water and foam and improve the distance of the robot.The fire extinguishing test shows that the robot has good fire extinguishing ability.The design of fire medium supply scheme greatly improves the fire extinguishing ability of substation firefighting robot,which is of great significance to ensure the safe operation of power grid.