Many plateau airports have been built in the west of China. The performance attenuation of aircraft in plateau airports will affect flight safety. In order to improve the safety of take-off from plateau airport, firstly, based on the analysis of the factors affecting take-off performance of aircraft in plateau airport, the influence of aircraft performance degradation on take-off performance of aircraft in plateau airport was studied from two aspects of the change of external environment and aircraft failure. Secondly, the risk of aircraft taking off from the plateau airport after performance degradation was sorted out, and the risk control process of take-off at the plateau airport was summarized. Finally, combined with the actual operation of plateau airport, risk control measures were formulated. The study shows that: 1) the influence of the flight performance degradation in the plateau airport security is more apparent, 2) the influence of aircraft performance degradation will be deepen after the superposition of bad weather, 3) takeoff performance calculation is one of the important measures to solve the aircraft performance degradation, 4) airlines should formulate risk control process and measures to deal with the safe take-off in the plateau airport after the aircraft performance degradation, and continuously optimize the process and measures according to the actual situation. 5) to manage the relevant operation control team well is an important measure to improve work efficiency.