Taiwan's IC industry sprouted in the 1970s, grew in the 1980s and flourished in the 1990s, this paper is to explore the critical successful factors (CSFs) in the process of development of Taiwan IC industry. From a historical point of view, the development of each industry, in fact, is composed of a series of events, each an industry event series about the people, places, things, time and other factors, this study first adopted the in-depth interview methods to collect research data, by visiting 27 experts in various fields of industry, government, academia, and researchm as the basis for the development of Taiwan's IC industry research. The next important research activity after getting the depth interviews was to perform survey research based on a questionnaire derived from the in-depth interview to various fields including industry, government, academia and research. After the data analysis found that: ＂The support of government policy-makers＂, ＂ITRI transfer the CMOS technology from RCA＂, ＂the establishment of the Hsinchu Science Park＂, spin-off the company UMC＂ and ＂spin-off the company TSMC＂ are the common critical events between questionnaires survey and in-depth interviews. In this study, the investigation of important industry development event is through a questionnaire, and gets the 17 factors influencing Taiwan's IC industry. By rating factors, we found that the most crucial factor affecting the development of Taiwan's IC industry is ＂smooth introduction of Taiwan IC technology＂, followed by the more important of the key factors in sequence as ＂IC human resoruce training and upgrading of relevant laws＂, ＂the culture of ERSO, Industrial Technology Research Institute＂, ＂IC technology continues to progress and the needs of a wide range of applications＂, ＂National scientific project spin-off private company＂ and ＂the vision of the top officer in the government＂. The survey also found that: The IC industry development of Taiwan in the past is generally considered ＂national policies and funds continued support＂ as the most key success factors (KSF), and hopes the future development of Taiwan's IC industry is generally agreed that it should first emphasize technology transfer and R&D. The government shifts from the dominant position in the past into the supporting role.