This paper analyses the key point of energy saving in the Wheeled Crane hybrid power system. The scheme of 25T Wheeled Crane hybrid power system is designed based on supercapacitor. DSP, PLC and Touch panel is used as the control center of the system. The design of main circuit, measurement system, PLC system and system communication and coordinate control is discussed. Finally, main circuit and system experiment results are presented. Experiment shows that this system may save energy 30% or above.