The wind measurement algorithm of the L Band Upper Air Meteorological Sounding System is discussed and the existing problems are analyzed. An improvement scheme for calculating upper air winds, which uses the average wind vector algorithm, is presented. Using the contrast observation data set from a ball launching simultaneously RS92 GPS radiosonde and the L band radar-GTS1 radiosonde at Xilinhaote and Yangjiang stations, comparison and analysis are conducted of the regular wind layer calculation results with a variety of average wind vector calculation schemes in the time window of 2 s to 200 s. Based on this analysis, it is suggested that in the time window of 30 s to 45 s, the average wind vector should be used for the future improvement of upper air winds measured by the operational L band radar and radiosonde sounding system, which can set a measurement wind layer every 150 to 350 m elevation, to further improve the consistency with the results of GPS measuring winds.