Abstract: Based on the feed-in&off-grid tariffs model of self-supply power plant, its ability to participate regulation of power grid is not fully utilized.The study puts forward the assessment mechanism of the responsibility tie line of the self-supply power plant, according to the AGC dispatch command, subtracting the plant loads of the self-supply power plant to obtain the equivalent dispatch command of the AGC and the equivalent output curve of the self-supply power plant; According to the equivalent output curve of the self-supply power plant to track the level of the AGC equivalent dispatch command to set different compensation electricity prices and assessment electricity prices. An example analysis is in progress with the actual operation data of a self-supply power plant in Northwest China. The calculation results show that the responsibility contract line assessment mechanism can effectively reduce the demand assessment cost of self-supply power plant by setting a reasonable equivalent AGC assessment bandwidth and compensation price, significantly improve the operational economic benefits of self-supply power plant and its enthusiasm for participating in grid regulation. Promoting regional new energy consumption,safe and stable operation of power grids.