为探寻中老铁路对云南省沿线地区经济发展的影响及作用机制，基于“一带一路”倡议和区域互联互通背景，以云南省中老铁路沿线主要站点地区为研究对象，构建加权平均旅行时间和可达性系数模型测算其交通可达性在铁路开通前后的变化情况，运用双重差分(Difference-in-Differences, DID)模型和中介效应分析2017—2023年面板数据，实证检验铁路开通的经济效应及传导路径。结果显示：①中老铁路开通使云南省沿线地区可达性平均提升28.9%，其中西双版纳和勐腊站点区域的改善幅度最大，提升超过35%；标准化可达性系数从0.79~1.25收敛至0.95~1.15，区域交通一体化显著增强；②铁路开通对沿线地区经济增长率的提升效应达1.6%，该效应主要通过固定资产投资驱动实现，但受城镇化公共服务供给改善滞后制约；③中介效应分析发现，铁路虽使外贸依存度提升6.1%，但其对经济增长的传导效应有限，产业结构高级化路径同样未显现。

In order to explore the impact and mechanism of the China-Laos Railway on the economic development of regions along the line in Yunnan Province, based on the background of the Belt and Road and regional connectivity, the paper took major station regions along the China-Laos Railway in Yunnan Province as the research objects, constructed the weighted average travel time and accessibility coefficient model to measure the changes in their traffic accessibility before and after the opening of the railway, and used the DID (Difference-in-Differences) model and mediation effect to analyze the panel data from 2017 to 2023 to empirically test the economic effects and transmission paths of the opening of the railway. The results show that: ①the opening of the China-Laos Railway has increased the traffic accessibility of the regions along the line in Yunnan Province by 28.9% on average, of which Xishuangbanna and Mengla station regions have the largest improvement, with an increase of more than 35%; the standardized accessibility coefficient converges from 0.79~1.25 to 0.95~1.15, indicating a significant enhancement in regional transportation integration; ②the effect of the railway opening on the economic growth rate of the regions along the line reaches 1.6%, which is mainly driven by fixed asset investment, but constrained by the lagging of public service supply improvement in urbanization; ③the analysis of mediation effects finds that although the railway increases foreign trade dependence by 6.1%, its transmission effect on economic growth is limited, and the path of industrial structure upgrading is also not apparent.