High-speed railway, as a modern means of transport with convenient, fast and mass transport volume characteristics, plays a significant role on regional development. Since 2008, in order to react to the influence of international financial crisis, China began the mass construction of high-speed rail. With the rapid construction, China has the longest mileage of high-speed rail in 2014. On the one hand, China enjoys the benefits of improved accessibility. On the other hand, many scholars think the expectations of high-speed rail are a bit exaggerated. In order to knowing and predicting the effects of high-speed rail objectively, the thesis tries to study how high-speed rail promotes the regional development in the Yangtze River Delta region of China, based on the experiences in Stockholm-Mälar Region of Sweden. The study in Stockholm-Mälar region suggests that: high-speed rail improve the overall accessibility in the region, and land along high-speed line and around station has better accessibility; frequent and easier commuting promotes regional integration; high-speed rail, on the one hand, strengthens the central position of regional center, on the other hand, brings more and equal opportunities for regional cities; moreover, large cities with good accessibility have the potential to grow up to the sub-centers. Combined with the experiences in the Stockholm-Mälar region and self-development situation, the development in the Yangtze River Delta region under the impacts of high-speed rail have following trends: first, high-speed rail promote the reorganize of urban system through the growth of new regional sub-centers and flat development; second, high-speed rail guides the reorganization of regional spatial structure, which mainly reflects in the urban land and regional cities distribute along the high-speed rail corridor; third, high-speed rail increases potential of regional commuting and accelerates the regional integration, and commuting trends will appear from major cities to Shanghai and peripheral cities to sub-centers; fourth, high-speed rail might bring positive effects (e.g. the radiation effect of regional central city) and negative effects (e.g. siphon effect, the outflow of city population and resources) for regional cities. In addition, aiming to the existing and possible issues, two supportive strategies are proposed about regional governance and urban public transportation development.