China and Southeast Asia share intimate relationships based on close spatial, temporal and human conditions. Thus, Southeast Asian studies in China boast of a long lineage of `traditional`, `embryonic`, `closed` and `opened` Southeast Asian studies. In the modern period the `embryonic Southeast Asian studies,` professing conservative nationalism based on traditional Sino-centric perspectives, accumulated elementary knowledges on the history of Sino-Southeast Asian relations and Chinese communities in Southeast Asia. On the other hand, `closed Southeast Asian studies` standing for radical Communism suffered from chronic stagnation. After the Reform and Opening, `opened Southeast Asian studies` recorded impressive progress in the restoration and development of Southeast Asian studies. Nevertheless, `opened Southeast Asian studies` are faced with some serious problems such as biased perspectives, traditional methods, and national subjects. Most of all, it is urgent to overcome Sino-centric perspectives on Southeast Asia. Despite the opening of Southeast Asian studies to the diverse methods of modern social sciences, descriptive studies prevail over analytical ones. Regardless of the diversification of subjects, national questions such as the overseas Chinese and cross-border nationalities are prone to excessive nationalism.