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Ecological Protection Construction and Its Impact Assessment on the Environment

: This paper selects Saihanba Nature Reserve in 1989 and 2017 and 18 nature reserves around Beijing as research objects for horizontal comparison, and constructs an ecological environment evaluation system, use TOPSIS and entropy weight method to calculate eco-environmental index. The results show that, after nearly 30 years of development, the eco-environmental index of Saihanba area has risen from 0.52 to 0.91, which means that the local environment has been greatly improved. An optimization model aiming at ecological benefits and costs was constructed, and the location, area, ecological benefits and costs of the 13 protected areas were obtained by solving with particle swarm optimization.