In order to resolve conflicts between economic growth and environmental protection, the mechanism of environmental impact statement (EIS), originally from the US, has been established in Taiwan from 1970s. The government hopes the controversy can be solved by science and technology, which are backbone of the Taiwan EIS. Unfortunately, many serious environmental protests still emerge against those development projects, whose EISs have been approved by the government. The paper tries to find out the approval rates of the Taiwan environmental assessment (EA) & (EIS) and make comparison with their rates of the US and European countries. The major question of the paper is whether Taiwan underestimates its environmental risk? The reports of EA and EIS in Taiwan invariably show that there will be no major harm to the environment or local people. It is because 85.9% of EA and 94.2% of EIS are accepted by “conditional approval” from 1996 to 2008. In the US, the approval rate is between 72.5% and 74.9%. Therefore, environmental risks in Taiwan are seemingly underestimated.