With the resurgence of new industrial districts like Silicon Valley in the United States, Baden-Württemberg in Germany, "The Third Italy"in Italy, regional technological innovation has been the focus of economic geography for 30 years(since 1980s). The purpose of this paper is to review and summarize the research findings of informal institutions and linkages of regional technological innovation in economic geography during the past 30 years. Based on the literature review of economic geography on the informal institutions and linkages of regional technological innovation, this paper proposes that theories and concepts such as "innovative milieu", "untraded interdependencies", "local buzz" and "spin-offs" have already raised and analyzed the attributes and features of informal institutions and linkages of regional technological innovation. Among them, the concept "innovative milieu" and "untraded interdependencies" mainly refer to informal institutions of regional technological innovation, while "local buzz" and "spin-offs" pay much attention to informal linkages. Moreover, the studies on the scale of informal linkages over-emphasis on the regional scale, and ignore the informal linkages of the national and global scale. Finally, this paper concludes that the research on informal institutions and linkages of regional technological innovation in economic geography is still in an early stage. Given that during the transformation period in our country, most linkages of technological innovation among firms within the region are informal linkages, it is meaningful for further studies on the causes and mechanism of informal institutions and linkages of regional technological innovation, and their effects on the innovation performance of firms.