The climate change and energy problems are making urgent demands on all countries in the world for low-carbon development. Smart grid will penetrate new types of technologies into power supply side， power grid side and power consumer side to promote the carbon reduction in power systems through coordination of multiple technologies. Based on the urgent need for low-carbon benefits evaluation system of smart grid， a technical route for evaluating from low-carbon capabilities to low-carbon benefits is proposed. Proceeding from the requirements of a comprehensive evaluation，the individual-low-carbon capabilities of smart grid to promote low-carbon development are proposed. Then the coupling between individual-low-carbon capabilities is deeply tapped and analyzed. For the request of avoiding benefits overlap， a model of integrated-low-carbon capabilities is developed， thus finally forming an integrated model for evaluating low-carbon benefits of smart grid. At last， the low-carbon benefits of smart grid are calculated and verified in a provincial power grid.