Some international scholars have turned their attention to a discussion of “civil understanding of science”, while more and more scholars in China have been discussing topics under the umbrella of “public understanding of science”. Albeit these two concepts are closely connected, the difference between them provides a new insight into the problems in the field of science communication. In this paper, the concept of “citizen” is analyzed through a discussion of the current state of the public understanding of science at both domestic and global level, and the difference between civic education, public education and common education is discussed as well. By adopting a typical case analysis of “citizens’ understanding of science”, the paper reveals the difference and distinctive meaning of delving into science communication from the citizen’s position or perspective rather than the view under the frame of “public understanding of science”.