This paper introduces a new design method of digital thermometer to achieve temperature display, which uses AT89C52 as the main control device, DS18B20 as the temperature sensor, and anode with a total of three LED digital tube to transmit data. Its hardware circuit includes the main controller, temperature measurement circuit and display circuit. Compared with the traditional thermometer, it has some strong points such as convenient reading, wide range of temperature measurement, and accurate temperature measurement. Its temperature output is displayed digitally. With the features of low-cost and easy-handling, it's mainly used in some places requiring accurate temperature measurement or research laboratories.