Based on the index data of the direct beneficiary area of Saihanba Machinery Forest Farm, this paper establishes the ecological environment assessment model for the period from 1990 to 2020; in addition, RSEI is established and applied to determine the site that can take in the Saihanba model in the country. Obvious impact of Saihanba Machinery Forest Farm on the ecological environment has been found since 2005 from the ecological environment score of the study object. According to the eco-index, the site area of the ecological zone to be built is 983,500 square kilometers, which is roughly 1:105 to the area of Saihanba Machinery Forest Farm.