In the cow breeding, cow oestrus detecting has an important position in cow breeding management, which can improve the cow's reproduction rate and milk production and increase the economic efficiency. Therefore, it is very important to identify cow oestrus in time and accurately. The traditional method of observing the cow oestrus is not adapted to the development of the modern dairy industry. This paper introduces the technology and design of cow pedometer based on STC89C52 microcontroller, ADXL345 accelerometer, and the development situation and trend of the cow pedometer based on acceleration sensor, achieving the display and automatic monitoring of the steps of cow walking.