The carbon humidity sensor's resistance is significantly influenced by temperature, resulting in upperair relative humidity sounding data errors. Through static tests on the sensors in the temperaturehumidity controlled chamber, the testing of the resistance changes was conducted under different temperatures. Based on the analysis and calculation on these lab data, the correction data of relative humidity and temperature were obtained, and the relative humidity correction equation was established, which can effectively correct the errors caused by temperature correspondingly. The comparison and analysis of correction on re al upperair relative humidity sounding data indicates that not only the accuracy of relative humidity data is improved after correction, but also the detailed variations in relative humidity at the upper atmosphere during the lower humidity period can be clearly manifested, which cannot be seen before correction.