On the condition of globalization world, cities have uprised and global urban hierarchy has formed, and this is a remarkable phenomenon in current economic and urban development. Study on world city has been emphasized by both foreign and domestic researchers since 1980s. In this article the authors firstly divide the process of research on world city into three phases, including the early research phase (before the 1980s), the world city theory formation phase(in the 1980s, the main sign is the publication of Friedmann’s World City Hypothesis)and the world city theory development phase (from the 1990s to the present). Meantime, the authors also conclude the main present schools and trends of the world city research as follows: 1) Sassen’s global city hypothesis; (2) the Los Angeles school, including scholars such as Scott, Soja, Davis, Jameson et al; (3) the study on the information technology revolution and world city development by Castells, Batten，Warf, Hepworth, Lanvin et al; (4)the study on world city network mutual function by Taylor, Walker, Catalano, Hoyler et al; (5) the study on the world city of developing country and area. Then, the paper in detail introduces and explains the main ideas of overseas scholars research on world city’s concept, functions, classifications, formation mechanism, world city network mutual function et al. At last, the authors simply analyze Chinese scholars’ research process and present situation on world city and some thought of constructing world city in China.