The helicopter hovering rescue simulator is applied to train helicopter rescue crews in harsh sea conditions of a helicopter rescue mission in laboratory.Stewart parallel platform is used as a dynamic generating device to the helicopter simulation cabin，because of its high rigidity,strong bearing capacity,and high precision.In order to ensure the trajectory of the simulation platform for helicopter hovering does not exceed its maximum boundary range,the working space of the platform were calculated and analyzed.The Stewart platform of helicopter hovering rescue simulation system was studied,and a solution of its working space based on the forward kinematics solution was presented.With a combination of the Stewart kinematics and the convex hull algorithm，the solution was accurate in operation,high in speed,and intuitive.Finally,the correctness of the method was verified by experiments.The method can be used to detect the motion state of helicopter hovering simulator under different sea conditions.