The flight track data analysis is important for the packing up the data in the exploration of the cloud physics and the atmospheric environment with aircraft. The discontinuousness of flight track data and conversion of geography data (longitude and latitude) are the issues that often occur in the GPS′s analysis. The new record system of the flight track with GPS in Cheyenne ⅢA was used in the project of the Beijing field experiment in 2004. The method of analyzing the data and checking out the badness log data including those discontinuous data is discussed with the Matlab′s function of matrix operation. The expressions for analyzing the geography data using the carry forward conversion are given.