This paper addresses a novel method to solve the three-dimensional pursuit-evasion game of Unmanned Aerial Vehicles (UAVs).Since this method combines the variational method with the pseudo-spectral method,it belongs to a semi-direct method.Firstly,the differential equations and its constraint conditions for solving the optimal control law of one player are derived by means of the variational method.Therefore,the differential game problem is transformed into an optimal control problem.Secondly,the optimal control problem is further transformed into a nonlinear programming problem by pseudo-spectral method.Finally,the SNOPT solver is utilized to obtain the numerical solution and simulation is carried out.The simulation results show that both players have adopted the optimal control strategies,which verifies the correctness,validity and rapidity of the method.