Abstract: Methane emissions of individual dairy cows during food digestion can be used as a reference for optimization of dietary formula in pasture feeding management. In this paper, an individual methane emission detection device for dairy cows based on non-dispersible infrared（NDIR） technology is designed. It adopts wearable structure, low power con-sumption and wireless transmission technology, and adopts dual-wavelength differential detection technology. The concen-tration of methane gas is calculated by using the analysis of Billebeau’s law. The device does not affect the daily activities and feeding behavior of cows. The designed signal processing circuit can effectively reduce the external interference. The response speed block can realize the real-time detection of data through the upper computer software.