Exchange Rate Risk Estimates of the Foreign Contracted Projects Based on the Model of VaR

China implements a floating exchange rate system after reforming the exchange rate mechanism in 2005. So far, nearly eight years, the RMB against the U.S. dollar increased from 8.2:1 to 6.1:1. Exchange rate risk of China's foreign contracted engineering industry has become a serious problem in the rapid development of the industry situation, this paper established exchange rate forecasting model base on the model of VaR through analysis the daily average exchange rate from July 22, 2005 to September 30, 2013, and estimate the rate of return by using the variance - covariance, historical simulation method, providing a theoretical basis for avoiding the exchange rate risk of China's foreign contracted projects.