Non - intrusive load monitoring（NILM）system has become one of the development trends of load monitoring in the future due to its less hardware installation, more accurate load analysis and better economy. The mainstream analysis method and system framework of non-intrusive load monitoring are introduced.Basic principle and algorithm floware summarized. The components of the non-intrusive terminal equipment systemare described.A practical non -intrusive residential power load monitoring terminal system is designed. On the basis of non-intrusive data acquisition, a power consumption behavior analysis model based on non intrusive data acquisition is proposed, which provides users with a detailed“thousands of people, thousands of faces”customized power consumption optimization scheme for individual household appliances, and realizes the visualization of non - intrusive terminal load, so as to further explore the value of data.