本文介绍了AT89C2051单片机的性能和特点，并在分析了超声波测距原理的基本上，指出了设计测距仪的思路和所需考虑的问题，给出了实现超声波测距方案的软、硬件设计系统框图。该设计系统经校正后，其测量精度可达0.1米。-This paper introduces the AT89C2051 MCU performance and features, and the analysis of ultrasonic distance measurement principle is basically that the rangefinder design ideas and issues that need to be considered, given the realization of ultrasonic ranging program of soft, System hardware design block diagram. The design system has been corrected, the measurement accuracy up to 0.1 meters.