Correctly predicting the passenger flow of an air route is crucial for the airline company to make sales policy. Because of the uncertainties and data inadequacy in the passenger flow prediction of the civil aviation, regression analysis and a grey prediction method are used for predicting and analyzing the passenger flow of the air route in 2016 based on the data of to-and-fro air route of an airline company over the past six years. After analysis on the solid evidence, the grey prediction method is proven highly accurate in the passenger flow prediction of the air route, and it can help to guide the airline company to estimate the passenger flow and therefore make the sales policy.