The study mainly explores whether major negative man-made events have great effect on value of publicly listed companies in Taiwan. Using recent food safety and environmental pollution events as example to examine relative stocks category and individual company’s stock via event studies, the study investigates whether market mechanism generates negative punishment on corporate value of inappropriate industry and analyzes the effect of different negative major man-made events on corporate value of relative stocks category and individual company’s stock. The event study applied in this study based on major man-made events in Taiwan to compute abnormal return and cumulative abnormal return after events occurred by market models, thus analyzing and comparing effect of each event on each industry. The empirical result shows that the same type of events have different effects due to directions of press reports, while the same events can generate different effects due to factors such as corporate structure, etc.