According to the literature on the subject and PAM framework (Ming-shen Wang, 2006), the cognition of the citizen of Kaohsiung in Kaohsiung development and direct cross- strait link could be influenced by three factors: the factor of economic development, the factor of social development, the factor of political development. The study applied category estimation and information integration theory (Anderson, 1996) to treat the citizen of Kaohsiung' s cognition structure, integration function, cognitive algebra, estimate etc. in Kaohsiung development and direct cross- strait link. The main research method in this study is information integration theory. It can figure the internal process of how individuals deal with a series of variables out, including valuation function, integration function and response function. And integration function is the key of information integration theory. Many researches of information integration theory mentioned that people always make use of simple cognitive algebra to integrate information, as adding rule, multiplying rule and averaging rule. The research result in this study is shown as below: 1. Although the middle and bottom classes in Kaohsiung considered that if opening direct cross- strait link, it can make economic development better, most people thought that it could make social development and political development worse. So they tend to oppose direct cross- strait link. 2. Most white-collar classes in Kaohsiung (including industrial circle, political circle, academic circle, grass-roots circle and mass media circle) considered that if opening direct cross- strait link, it can make economic development, social development and political development better. So they tend to assist direct cross- strait link. 3. In group analysis, the information integration of the industrial circle in " acceptive situation of Kaohsiung development" is different-weight averaging model. They pay much attention to economic development. 4. In group analysis, the information integration of the political circle in " acceptive situation of Kaohsiung development" is different-weight averaging model. They pay much attention to economic development. 5. In group analysis, the information integration of the academic circle in " acceptive situation of Kaohsiung development" is different-weight averaging model. They pay much attention to economic development. 6. In group analysis, the information integration of the grass-roots circle in " acceptive situation of Kaohsiung development" is different-weight averaging model. They pay much attention to social development. 7. In group analysis, the information integration of the mass media circle in " acceptive situation of Kaohsiung development" is different-weight averaging model. They pay much attention to economic development. 8. In individual analysis, 60% people pay much attention to economic development, 22% people pay much attention to social development, and 18% people pay much attention to political development.