Abstract: Under the background of the development of new power system, in order to further clarify the supporting mechanism of photovoltaic power generation auxiliary service for low-carbon and high-efficiency operation of the system, a system electric carbon energy efficiency measurement system is constructed based on the collaborative mode of photovoltaic inverter and SVG device. Firstly, based on the traditional carbon flow theory, a system dynamic carbon flow calculation method considering photovoltaic power generation auxiliary service support is proposed. Based on the correlation analysis of system electricity and carbon indicators, a three-stage electricity and carbon energy efficiency measurement analysis model of the system considering the influence of external environment and random error is constructed, which lays a foundation for quantitative analysis of the correlation between photovoltaic auxiliary services and system energy consumption, line loss rate and carbon emissions. At the same time, combined with the improved IEEE 14-bus system, the simulation is carried out to reveal the dynamic influence process of photovoltaic auxiliary service on system energy consumption, line loss rate, voltage deviation and carbon emission, and its support mechanism for multi-scale energy saving and carbon reduction of the system. The analysis results show that the photovoltaic power generation auxiliary service in multiple periods plays a supporting role in reducing the active energy consumption, reactive energy consumption, line loss rate and carbon emissions of the system. On the other hand, through the application of the proposed method, the weak links of the power-carbon coupling operation efficiency of the system are effectively identified, which provides a basis for the system scheduling optimization decision-making, and provides a case reference for the low-carbon planning and auxiliary service market mechanism design of the new power system.