对口支援是中国经济发展中的一项重大举措。文章将19省市对口支援新疆视为一项准自然实验，选取2005—2020年新疆南疆四地州县域面板数据，采用双重差分法识别对口支援政策驱动南疆四地州经济内生增长的净效应。研究发现:对口支援政策的实施显著促进了南疆四地州自我发展能力的提升，但政策效果的显现存在时滞性，直至2015年该政策才在南疆四地州自我发展能力各维度均表现出显著的促进作用。此外，因南疆四地州各县市经济基础、要素禀赋等存在差异，故对口支援政策效果不尽相同，在自我发展能力较高的县市政策效果明显，而在自我发展能力较低的县市政策效果不明显。

Pairing assistance program is an important regional development strategy in China, as well as an important measure to consolidate poverty alleviation achievements and comprehensively promote rural revitalization. In this paper, 19 provinces and municipalities paired up to help Xinjiang as a quasi-natural experiment. Based on the county-level panel data of the four prefectures in southern Xinjiang from 2005 to 2019, this paper identifies the promoting effect of the corresponding support policies on the self-development capacity of the four prefectures in southern Xinjiang by using the difference-in-differences method. The results show that the pairing assistance policy has significantly improved the self-development ability of the four prefectures in southern Xinjiang, but there is a certain time lag in the implementation of the policy effect. Until 2015, the policy has significantly promoted the four aspects of self-development ability of the four prefectures in southern Xinjiang. At the same time, due to the differences in economic foundation, factor endowment and other aspects of the counties in the four prefectures of southern Xinjiang, the effects of pairing assistance policies are not the same. In counties with high self-development ability, pairing assistance policies have a significant positive effect on the improvement of self-development ability, while in the counties with low self-development ability, the effect of the pairing assistance policies are not obvious.