Abstract: Based on the experiences of managing risks of civil aviation companies, a Value at Risk (VaR) procedure was proposed to control overbooking risk．The calculation method of extra number of single-line and the representation of VaR of multi-line were given respectively． One whole company's VaR in a day was obtained from analyzing the relativity of return about different flights. Finally, an example on the risk analysis of one scheduled flight from Beijing to Hongkong was given to demonstrate the feasibility of VaR in the risk management of civil aviation transportation.