Large-scale sports events will drive urban or even national economy rapidly development, which is a ge neral agreement. The paper takes Beijing Olympic Games as an example; it studies on large-scale sports event s to urban impacts and makes evaluation. In grey GM(1.1)model, according to passenger volume reception per month during 2003 to 2007, it predicts passenger volume receptio n in every month of 2008, according to measurement and actual value comparison, it gets changing impact values. I t has maximum proportion in Tertiary industry, seco ndly is Beijing per capita GDP, the lightest proportion is number of passengers reception, make normalization processing with three weights, and makes comparative analysis.