Using digital twin technology, grazing monitoring system was set up on the basis of sensing pasture environment and livestock status. In this system, the virtual simulation technology Unity3D was applied to the twin three-dimensional model of pasture grazing scene to present the visualization effect for follow-up monitoring. Wireless transmission technology was used to build a collection network to realize the function of information interaction between pasture and livestock, and fuzzy comprehensive evaluation method was used to classify grazing intensity of pasture. In order to verify the effectiveness of the system, the real scene of Maodeng Pasture in Xilinhot City, Xilin Gol League, Inner Mongolia was taken as a testing example. The results showed that compared with the traditional grazing monitoring system, the system used digital twin technology to realize data sharing and synchronization of physical pasture and twin pasture information, and effectively solved the problem of decision-making lag in the traditional grazing monitoring system. Through the twin pasture, the grazing scene of the physical pasture could be simulated, which was not restricted by objective conditions, and could effectively predict various grazing conditions, achieve accurate monitoring of the pasture environment and livestock grazing state, and timely respond to emergencies in actual grazing, improving the autonomy of grazing decision-making of the pasture.