The wind power industry has developed rapidly in China, but the effect of wind power projects on the ecosystem is far from being clearly understood. The objective of this study is to evaluate the negative impact of wind power plants on the ecosystem. In this research, least-cost distance and least-cost path models were employed to establish potential ecological corridors based on the resistance at the site of the wind power projects––which is located in the ecological function area in Qinyuan, South Shanxi Province, China. The landscape connectivity was evaluated using a set of connectivity indices. In addition, the impact on the corridor patency, length, and the connectivity between ecological corridors were analyzed. The results showed that the wind power projects could not only significantly increase the migration resistance that hampers the formation of ecological corridors of the species at the landscape scale, but also had an obvious cutting effect on the landscape––resulting in an increase in the length of the ecological corridors and a decrease in corridor patency and landscape connectivity. There was also a positive relationship between the increase in length and the distance between the source patches. In addition, the connectivity was enhanced with the increase in distance threshold. This study evaluated the ecological impact of onshore wind power projects at the landscape level, filling the gap in research on landscape ecology, especially in the protected area with key ecological function. Meanwhile, the results are beneficial to guide the location selection for wind power projects and minimize their negative impact on the key ecological corridors.