To solve the problem of inconvenient assembly-disassembly of blocking plates of the main pipe of a steam generator,a six DOF robot configuration is proposed.On the basis of analyzing the forward and inverse kinematics of maintenance robot,the D-H parameter model of the robot is set up.The three-dimensional image,projection and profile of the robot working space are obtained by using Monte Carlo method to simulate and analyze the working space of the robot.The external 3 Dgraphics and internal space outline of the robot workspace are constructed,and the method of determining the working range o...