Tethered balloon sounding system was used to measure the profiles of wind speed, temperature and humidity of the atmospheric boundary layer in Changzhou, Suzhou and Nanjing. The original data show that the observational results have systemic errors. Therefore the error correction method of wind speed was discussed in this paper. Analyses show that the error of wind speed was concerned with height and the magnitude of wind speed, so two methods of error correction, the height-related scheme and the speed-related scheme, were proposed. The corrected results indicated that the two methods can remove the error effectively, and the height-related scheme was much better. Furthermore, the corrected wind speed from tethered balloon sounding was compared to that from wind profile radar at Suzhou Meteorological Bureau, and the results show that the wind speed detected by wind profile radar was generally underestimated from ground to an elevation of 500 m.