Abstract: The roadway repair robot undertakes the operation task of coal mine roadway repair. The agile and efficient operation mechanism is the key component of coal mine roadway repair robot for flexible, efficient and autonomous operation, which determines its operation space and limit operation size. Aiming at the disadvantages of inflexibility and low operation efficiency of the existing coal mine roadway repair robot operation mechanism, a 4-DOF three arm coal mine roadway repair robot operation mechanism is proposed. The kinematics model of the operation mechanism is established based on the D-H parameter method, the forward and inverse kinematics of the operation mechanism is analyzed, and the relationship between joint rotation angle and end displacement with time is obtained. The working space and limit working size of the designed working mechanism are simulated and analyzed by using virtual prototype technology and Monte Carlo method respectively. The results show that the rotation angle of each joint changes smoothly and there is no sudden change. The working space obtained by the two analysis methods is similar, and the deviation of working limit size is less than 5%, and are better than the design value, which indicates that the operation mechanism meets the expected requirements. The research results have reference value for the design of agile and efficient operation mechanism of coal mine roadway repair robot.