Using observed microclimatic data,we analyzed the microclimatic characteristics over irrigated shelter forest land and the external influence factors in Tarim Desert in autumn and make the comparison with shifting sand land. Results showed that the irrigated shelter forest land had particular climate functions,such as modifying surface temperature differences,reducing soil temperature,and improving humidity. Surface temperature between shelter forest land and shifting sand land had significant difference. Surface soil temperature in shelter forest land was lower than that in shifting sand land in the daytime,whereas it was contrary in the nighttime. The daily difference of surface soil temperature in shifting sand land was 18.26 ℃ higher than that in shelter forest land. From 09:00 to 15:00,the average air temperature in shelter forest land was 1.44 ℃ higher than that in shifting sand land,whereas in other time,it was 3.22 ℃ lower averagely. The difference between shelter forest land and shifting sand land in the daylight was greater than that in the night. The daily difference of air temperature in shelter forest land was 4.41 ℃ higher than that in shifting sand. Air absolute humidity and relative humidity in shelter forest land was higher than those in shifting sand. Microclimate among different shrubs species exhibited the different characteristics but no significant difference. Soil surface temperature,air temperature,and humidity between different forest covers showed the different characteristics. The observed results are of significance to further exploring material and energy exchange near surface layer under irrigation condition in the extremely arid conditions.