To overcome the defects of traditional temperature detecting devices, this paper introduces a temperature detecting system based on 1-wire digital thermometer DS18B20. It consists of programmable resolution 1-wire digital thermometer DS18B20, single chip microcomputer (SCM) AT89C51, and the peripheral circuits. The temperature data can be displayed on a liquid crystal display and simultaneously transmitted to a personal computer (PC) via serial interface for remote monitoring after it is detected by sensors. The operating process of DS18B20 and the connection between AT89C51 and PC are introduced in detail. We also provide the main program flowchart and the flowchart of accessing DS18B20 in this paper. The simulation of the whole process is successfully implemented with software PROTEUS. This system can be widely applied in environment monitoring and process control.