The radiosonde temperature observation data collected at the Sheyang station throughout 2014 are analyzed，and it is discovered that the detection errors caused by air moisture are very common．When temperature sensors transferring from high humidity area to low humidity area，the observed temperature will become lower than environmental temperature due to water evaporation． Inconsistent air temperature, moisture distribution， and phase states of water in the atmosphere result in disparate errors in the collected data. Several practical cases, as examples, are selected to perform simple experiments，and the potential influences of air moisture on radiosonde temperature observations are discussed．