The invention relates to an inspection robot path planning method suitable for the indoor switch room of a transformer substation. A transformer substation operator sends the instruction of patrollingat least one interval to an inspection robot through a wireless local area network. After receiving target interval position information, the inspection robot enters into the path planning mode of arriving at a target interval position. And then, through combining laser data acquired by a laser sensor loaded by the inspection robot and a speedometer with an observation model, the pose of the inspection robot is accurately positioned. The inspection robot continuously explores surrounding spaces according to the accurate positioning of a current position, and uses a rapid random generation tree RRT algorithm to calculate the optimal path of arriving at the target interval position. And the target interval position is arrived. In the invention, an environment in a switch cabinet is randomlysampled, searching is guided to a blank area, obstacles on a walking route are avoided and an optimal path plan from a starting point to a target interval is searched.