Since scientists became a major participant in the decision-making of public policies in modern society, social science researchers have conducted in-depth researches into issues related to scientists’ participation in public decision-making from different perspectives. Basically research approaches on two levels are taken throughout relevant researches at home and abroad, namely, policy science and science, technology and society (STS), which examine the overall relationship between science and the government on a macro-level, and knowledge utilization theory, which scrutinizes the mechanism of scientists’ knowledge utilization and its influencing factors on a micro-level. This chapter reviews the researches that have used the aforesaid approaches, summarizes academic explorations of determinative factors of scientists’ influence on S&T decision-making and indicates the potential theoretical development of our research.