At present, China's truck crane is often out of the crane and the crane operator safety considerations, was given a larger design safety factor in the load circuit into a larger load, resulting in a hoisting mechanism hydraulic system is very Large energy loss. The mathematical model of the closed-loop control of the hydraulic system of the hoisting mechanism is established. The AMESIM software is used to carry on the dynamic simulation research. The constant power closed-loop control strategy of the hydraulic system of the hoisting mechanism of the crane is obtained, which reduces the energy loss of the hydraulic system. Thereby improving the energy saving of the hydraulic system of the hoisting mechanism.