Aviation Safety Council (ASC) is an independent aviation occurrence investigation agency of Taiwan, R.O.C. In order to prevent similar occurrence from happening again, the ASC always keeps the spirit of its core value since established in 1998: "Professionalism", "Independence", "Integrity", "Internationalism" and "In search of excellence" (PI4) to perform investigation. Until now, the total number of investigation conducted by ASC and assisting foreign country's investigations are 97 cases. Totally, 736 flight safety recommendations were brought up after the end of those investigations. This paper briefly reviews some significant cases that the ASC has investigated and describes the attributes and causal factors and the fruitful effects of related flight safety recommendations of each case in accordance with its time sequence. According to the classification and analysis of cases investigated, five results were obtained. Based on the results, we would like to share our efforts with airlines operators and related authorities. Besides, the development of ASC's investigation techniques, regional technical cooperation and international information sharing are also reviewed in the paper. Finally, the future goal of the ASC is described.