Abstract: In view of the problems that the data acquisition system of microcomputer relay protection of underground high-voltage distribution device has not good real-time ability,the paper proposed a design scheme of real-time data acquisition system for mine-used high-voltage distribution device based on TMS320LF2407 DSP and 14-bit A/D chip MAX125.It expounded hardware circuit design of PLL,data acquisition circuit and the system software.The experiment result showed that the system has good performance such as real-time,accurate and reliable in data acquisition.