Abstract: In order to realize navigation and positioning of roadheader in combination with inertial navigation technology,a positioning method of roadheader based on four point light target is put forward.The characteristics of the four point type optical target are described.The system positioning mechanism is analysis.The mathematical model is established.The effect of main parameters on the calculation model of the research is simulated.The simulation results show that the high estimation accuracy on lateral offset when the yaw angle is less than 15 degrees,and is not sensitive with the distance between the roadheader and the device.The simulation results show that a poor estimation accuracy to the distance;the experiment device is built and a test is completed by the total station.The test results show that the maximum positioning error of the proposed method is 0.063 mm in the section within the range of about 39～94 m away from the target.The maximum deviation from the direction of the roadway is 1.064 m,and the farther the distance,the greater the deviation and the basic rules and simulation results is verified.The positioning method of roadheader based on the four point light target can meet the accuracy requirement of automatic navigation and positioning of the roadheader with the combination of inertial navigation system.