Abstract: Located in the northwest of China,the Lanzhou-Xinjiang high-speed railway is the only railway line that connects the western part of Gansu Province and Xinjiang,China.In this paper,the research scope is taking one-hour driving distance (60 km) in the provincial highway as the radiation range of high-speed rail,and thus 91 counties and autonomous prefectures are extracted.Based on the accessibility of the grid,the basic road network and socio-economic statistics of the three provinces including Gansu,Qinghai and Xinjiang in 2015 are adopted.Also,the methods and models of weighted average travel time,isochronous circle,economic potential and spatial variogram are used to evaluate comprehensively the temporal and spatial convergence effects and economic potential changes of the weighted travel time within the research unit before and after the Lanzhou-Xinjiang high-speed railway is opened.All done is expected to better serves the regional development and provide theoretical support scientifically for regional coordinated development.The results show that the opening and operation of the Lanzhou-Xinjiang high-speed railway can do a great job.Firstly,the weighted average travel time of 91 county units along the line shortened by 33.46%,which increases from the core area of the high-speed railway to the periphery in turn,showing a “core-edge” structure.Compared with core cities,the role of accessibility and optimization in small and medium-sized counties are relatively stronger.Secondly,the accessibility of the high-speed rail station cities and other central cities has risen significantly,in which there are obvious “node effect” and “corridor effect”.The opening and operation of Lanzhou-Xinjiang high-speed railway has reduced the regional accessibility difference as a whole,while the high-speed rail stations and their adjacent areas gain the largest accessibility benefits.And the spatiotemporal convergence is in line with the law of the geographical distance attenuation to a certain extent.Finally,the regional economic potential as a whole has developed in a balanced way,stimulating the economic development of cities and towns along the line.At the same time,the evolution of economic potential has become more and more prominent in its hierarchical feature.Above all,measuring the impact of traffic improvements on regional development and socio-economic effects under different scenarios,speeds and conditions would have a positive guidance for future research on regional economic development along high-speed railway,national traffic planning and its strategic layout．

Key words: accessibility, time-space convergence, economic potential, LanzhouXinjiang high-speed railway