本文介绍了以"一线总线"的数字方式传输的DS18B20温度传感器为测温核心，用单片机AT89S51构造控制电路，利用数码管及其它外围元件组成显示单元，通过ISP方式进行程序的编制、用并口连接线下载单片机程序和以MAX232 芯片设计RS232串口电路并通过串口连接线进行调试，设计、制作了一种电子测温计。-This article describes the " bus line"　of the digitally transmitted DS18B20 core temperature sensor for the temperature measurement, control circuit with a microcontroller AT89S51 structure, the use of digital control and display unit composed of other peripheral devices, by way of programming for ISP, with parallel port connection line procedures and to download MAX232 chip microcontroller RS232 serial circuit design and debugging via serial cable, design, production of an electronic thermometer.