According to the theoretical analysis of the influencing factors of power consumption and engine output power of cold milling machine, the working speed of the machine was selected as the power adaptive control parameter. On this basis, a simulation model of the system is established, and the use of engine power and its operation efficiency before and after using the adaptive control system are simulated and verified. The results show that it is reasonable and effective to select the machine operation speed as the power adaptive control parameter. The power adaptive system can automatically adjust the machine to work near the rated power of the engine, which improves the rated power utilization rate and operating efficiency of the machine by more than 10.2% and 6.32% respectively under the given conditions. This study provides a reference for rational use of engine power and improvement of machine operation efficiency.