The present invention discloses a calculation method of an energy saving and emission reduction development object contribution rate. The method comprises the following steps: S1, calculating thermal power plant generation side carbon emission; S2, obtaining social electricity consumption load prediction and power supply planning in an area and electric power exchanging data at the outer portion of the area; S3, establishing the calculation method of the contribution rate of non-fossil energy generation supported by an area power grid to the national non-fossil energy consumption amount; and S4, establishing the calculation method of the contribution rate of the area power grid to unit GDP energy saving and emission reduction.