In accordance with the data of radio sounding data and the data of surface temperature and precipitation in Northeast China in 1971-2005, the temporal and spatial change characteristics of free atmospheric specific humidity and relative humidity as well as the relationship between humidity and surface temperature and precipitation are analyzed. The results indicate that, the spatial distribution of specific humidity is impacted by water vapor source in Northeast China, decreased from the southeast to the northwest on the ground, and decreasing from the south to the north at upper air. The spatial distribution of relative humidity is impacted by water vapor, altitude and latitude, decreased firstly and then increased from the south to the north from the ground to lower layer of troposphere, increased from the south to the north in the mid layer of troposphere, and the southwest-northeast drought tongue from Chifeng to Tongliao is the most obvious, and gradually weakened with height increased. In 1971-2005, annual and seasonal specific humidity exhibited increasing trends from the ground to upper air, the increasing trends in the mid to lower layer of troposphere. The annual and seasonal relative humidity decreases significantly on the ground, and increases significantly in the mid layer of troposphere. The positive correlation between free atmospheric specific humidity and surface temperature is significant on annual and seasonal time scales. The negative correlation between free atmospheric relative humidity and surface temperature is significant on seasonal time scales. The correlation between relative humidity in the mid and lower layer of troposphere and precipitation is significant. The increased temperature is played an important role in climate changing to aridity of Northeast China. The increase of upper relative humidity helps add precipitation. The changes of surface temperature and water vapor content have impact the change of drought and humid climate.