Abstract: Flight simulators are susceptible to external disturbance and parameter variation. To solve this problem, we propose a global sliding mode control (GSMC) method based on the disturbance observer (DOB) for the flight simulator. We use an integral switching function to set the initial state of the system on the sliding surface in order to solve the reaching phase problem. Then we design the sliding mode controller to guarantee the global sliding mode property. To suppress chattering in control input, we introduce a disturbance compensation part based on DOB. Then the switching gain only needs to be greater than the upper bound of disturbance estimation error. Experimental results show that the proposed method possesses strong robustness against uncertainties, great chattering suppression in control input, and good tracking performance.