To solve the problem that general optimize algorithms couldn’t effectively calculate the designed variables with complex restrictions,a hydraulic pump/motor displacements and their rotate speed restrictions rule based knowledge-base(RKB) was proposed,and the RKB adaptive simulated annealing genetic algorithm(ASAGA) was introduced to optimize the main components and system parameters of wheel drive hydraulic hybrid vehicle(WDHHV) driving system.The energy saving and propulsion characters of the optimized WDHHV were analyzed by simulation,and simulated experiments of the WDHHV with a start-stop-start working cycle according to the corresponding energy were carried out.All the simulation and simulated experiments results show that the proposed RKB ASAGA is reasonable and effective,and the energy saving and propulsion characters of the optimized WDHHV are all better than that of the traditional vehicle.