Abstract: The PHA method is a system safety analysis method that analyzes various risk factors，occurrence conditions and possible consequences of accidents in the early stages of the project. It has the advantages such as simple and easy to use，low operating cost，being well organized，rigorous analytical structure，short analysis cycle etc. Based on a large amount of collected information，this study used PHL analysis and PHA analysis methods to identify various hazards，dangerous effects，danger grades and hazard levels existing in climbing formwork technology of cable- stayed bridge pylon，and then formulated corresponding prevention and control measures. In order to prevent the occurrence of accidents，we can achieve the forward-looking and pre-control of safety control with the analysis method. Through the implementation of this scheme，the PHA method was used to analyze and prevent the construction safety risk in climbing formwork technology of cable- stayed bridge pylon，and the feasibility and reliability of the method were studied.

Key words: climbing formwork technology, safety system, preliminary hazard analysis (PHA), LEC, safety risk, control measure