Abstract: This is an empirical study about urban internationalization. The development of global city or international city in China has been debated for nearly a decade. Nevertheless, few researchers have ever shed light on the outcome of such strategies. As a case study, this paper examines the level and process of urban internationalization in Guangdong Province, the most opening region of China. The paper firstly builds a comprehensive indicator system to evaluate the level of urban internationalization. All indicators are divided into core and basic types according to their implication upon the process of internationalization. Second, based upon the quantitative data from multi-channels such as Statistical Yearbook, it calculates the international levels of 21 cities in the years of 1985, 1990, 1995, 2000 and 2003 in Guangdong Province, showing the change of urban internationalization levels of these cities during last two decades. According to the quantitative analysis, all the 21 cities are divided into three categories: rapidly growing group, continually slowly growing group and fluctuating group. This indicates that although all such cities have undertaken policies of open-door and internationalization, the extent of changes are by no means the same. In addition, both qualitative and quantitative methods are used to uncover the underlying mechanisms. Socio-economic as well as cultural and historical factors of the cities are examined. On the basis of the study, three conclusions are found. First, after two decades of market reforming, the internationalization level of the cities in Guangdong Province have largely increased. Although none of such cities are truly so-called global city, they are undergoing unprecedented restructuring closely related to global forces. As such, the strategy of open-door has successfully developed a system of globalizing cities in the region. Also, this indicates that internationalization/globalization has tremendous impact on cities on the lower level of the global city hierarchy. Second, the internationalization development is not the only phenomena of the so called Word City and Global City. Rather, it is a widespread process in nearly every city in the world. Even more, the extent of impact by internationalization upon cities is rooted in the regional context of such globalizing cities. It is highlighted that historical, political and cultural factors are significantly factors underlying the process. Different cities have undertaken varied channels to raise their status on the hierarchy of globalizing cities. Third, it is found that the change of urban internationalization is not a linear growing process, but a fluctuating process with occasional growth and decline for most cities. This shows that the process of internationalization is complicated. The level of urban internationalization is not only a result of forces oversea, but also the result of the local variables including both geographical and social conditions.