Abstract: The perception of degraded environment in coal mine limits the application of visual measurement technology. At the same time, the long-term and low-speed operation characteristics of roadheader make the error of inertial navigation system accumulate and enlarge with time. Aiming at the above problems, an integrated positioning method of roadheader based on factor graph optimization fusion vision and inertial navigation is proposed. Firstly, the infrared target is manually set as the feature target, and the visual pose measurement system of the roadheader based on the infrared target is constructed. The explosion-proof infrared binocular camera collects the infrared target image. Through the extraction of the feature points and the binocular vision pose observation model, the visual pose observation of the roadheader is obtained. Secondly, the explosion-proof inertial navigator installed on the body of the roadheader obtains the angular velocity and acceleration of the roadheader in real time. The inertial pre-integration is used to preprocess the inertial navigation data to obtain the inertial pre-integration observation. Finally, the factor graph optimization method is used to fuse the visual and inertial navigation data, and the visual factor and inertial factor are constructed based on the residual function. The objective function is solved by nonlinear optimization iteration to obtain the optimal estimation of the roadheader pose. The ground test results show that the absolute average position errors of the proposed method in x, y and z directions are 0.004m, 0.027m and 0.005m, respectively, and the absolute average errors of roll angle, heading angle and pitch angle are 0.04°, 0.78° and 0.39°, respectively, which are better than the fusion results of KF and EKF. The underground test results show that the average errors of the roadheader in the x-axis, y-axis and z-axis are 0.015m, 0.015m and 0.014m respectively, which can meet the requirements of the positioning accuracy and stability of the roadway excavation operation.