The basic function and composition of adaptive switching input data acquisition system is introduced according to the design process of new generation high-voltage relay protection. A system design and software identification method for the data acquisition of the adaptive switching value of Power System Secondary Equipment is proposed. According to the optocoupler acquisition loop and experimental verification on the design of adaptive switch data acquisition system, the hardware and software implementation method of the data acquisition system is described. By software the system can adjust the threshold value of the adaptive switching input voltage and monitor switching power supply voltage. This system has a very important role in improving the success rate of hardware research and development, and improving the stability and reliability of the power system secondary equipment.