The energy-saving control of the power system of construction machinery focuses on the power management control among load, power and fuel consumption. By comprehensively considering the whole machine power matching, engine energy saving, load adaptation and other factors, the speed fluctuation factor was introduced to dynamically evaluate the load stiffness of the engine, and the system match was real-time dynamic adjusted. The working condition adaptive energy-saving control system for the new concrete pump was developed, and the experimental research and effect verification were carried out. The results show that the problem of poor load adaptability is effectively solved, and the fuel saving is 11.1% more than the existing energy-saving system.