Temperature and humidity characteristics of soil and air at different levels are analyzed based on theobserved data of typical forest ecosystem of Heihe River basin in 2008.Results show that:（1）Soil temperature at different depths is the lowest between February and March each year and the highest between July andSeptember.Annual temperature difference and minimum soil temperature decreased with the increase in soildepth.（2）The moisture of top soil is greatly affected by snowmelt in spring and rainfall,reaching its maximum value in the middle or last ten days of August.There is less impact of snowmelt in spring on the soilmoisture between 20and 40cm from soil surface.The soil moisture content between 80and 120cm is quitestable and is not influenced by snowmelt in spring.（3）Air temperature at different heights in forest presentsa declining trend from the middle of July to the last ten days of January next year and then increases continuously from the early of February to the early of July.Air temperature at 2mheight is a bit warmer than that at 10and 24mheights.The highest and lowest daily temperature peaks are observed at about 14:30and 6:30,respectively.（4）Air humidity in forest is lower between April and June and higher between June andOctober.The maximum and minimum relative humidity values are observed at about 22:00and 11:30,respectively.The humidity variation at 10or 24mheight is similar to that at 2mheight.