The article discussed the relation between the economic & trade law and the economic development in Taiwan after World War II from an internal perspective of legal system as well as an external perspective. The author described the forgoing relation by observing the interaction between the legal system and the actors in the economic development process. The author indicated that there were four periods presenting characteristics of legal system during the process of economic development as follows: (1)1945-1960: legal system under the buildup of high regulation policy; (2) 1060-1980: legal system under the rapid economy development; (3) 1980-1987: legal system under the politic and economic crisis of the state.; (4) 1987-now: legal system under the liberalization and democratization. The legal system, consisting of characters of regulation, subsidization, de-regulation, liberalization and re-regulation, became an efficient tool for the state to lead the market. However, because of the legitimacy that the legal system could provide for the state, it also influenced the behaviors and strategies of actors including state, labors and capitalists during the economic development process.