中文摘要：

基于时间和经济两种维度，以哈大与郑西两条欠发达地区高铁线路为研究对象，利用加权平均旅行时间与经济潜力综合测度两条高铁运营前后沿线城市可达性的动态变化及空间差异，结果表明：高铁开通后，沿线城市可达性明显改善，哈大高铁可达性综合改善程度强于郑西，且内部可达性变率相对差异较小；哈大高铁可达性交率呈线路中间大、首末小的态势，郑西高铁经济潜力变率呈自东向西递减趋势；哈大高铁明显提升了吉林南部与辽宁北部的核心地位，可达性获益的空间集聚效应凸显；郑西高铁显著拉近了中原和关中地区，以郑州、洛阳、西安为核心的“古都经济带”初露端倪，未来可向西对接“丝路经济带”，打造沟通中国与欧亚大陆跨国经济走廊。

英文摘要：

Based on the data of average travel time of all the trains in high-speed rail stations, the paper selects Harbin-Dalian high-speed rail and Zhengzhou-Xi＇an high-speed rail as the research objects in the north- east and mid-west less developed regions. And the paper selects the weighed average travel time and the economic potential as the main evaluation indicators. Combining with the spatial analysis tools in ArcGIS software, the paper uses the accessibility model to evaluate the spatial differences of urban accessibility improvement degree and the spatial pattern evolution before and after the Harbin-Dalian high-speed rail and Zheng- zhou-Xi＇an high-speed rail opening. The results show that： After the Harbin-Dalian high-speed rail and Zhengzhou-Xi＇an high-speed rail opening, the accessibility of cities along the high-speed rails has improved obviously. Comprehensive accessibility improvement degree of Harbin-Dalian high-speed rail is stronger than the Zhengzhou-Xi＇an high-speed rail. And the accessibility of internal variability is relatively smaller in the Harbin-Dalian high-speed rail. The weighed average travel time is mainly affected by the urban spatial distance and frequency of high-speed rail connection. The economic potential is always influenced by the urban economic strength and interaction intensity. As the same time of improving accessibility of cities along the high-speed rail line, high-speed rail also enlarges the accessibility gap of some regions. The marginaliza- tion degree of some regions has deepened because of obtaining less beneficial accessibility. The overall unbalanced situation intensifies the Matthew effect.