Abstract: China's national new districts are comprehensive functional areas that undertake the strategic tasks of the country's major reform and innovation. They should be the vanguard of promoting regional green development. The panel data from 2006 to 2016 of prefecture-level cities in China and the DID method were used to investigate the impact of establishing China's national new districts on regional green development. It is empirically found that the policy effect of establishment of China's national new districts on the green development of the province is apparent, but there is regional heterogeneity in the green development of main cities. Further, there is no threshold in the driving effect of China's national new districts on the green development of other cities in the same province.