Abstract: Taking Guangshan County of Henan province "12·19" formwork collapse accident as an example, the fault tree analysis method was used to analyze the causes of accidents and safety hazards in the process of the accident in details, the scientific and effective preventive measures were put forward according to the results of the analyses. The results showed that there were 48 possibilities to cause the construction formwork collapse accident, but as long as any group of the 3 groups taking the minimum path set took effective preventive measures, the accident can be avoided.