To estimate the dimension of CO_2 producing and letting in permafrost regions of the Tibetan Plateau,alpine dry grassland(Cab-Gel-Sandic Entisols),alpine meadow grassland(Cab-Mat-Cryic Cambisols) and alpine grassland(Cab-Hap-Cryic Cambisols) in Beiluhe Region were chosen for study.The distribution characteristics of CO_2 conceration in soil profiles and the CO_2 concentration in the soils at different times were studied in three sites.The results showed that there existed similitude for the distribution characteristics of CO_2 concentration in the three soil profiles,decreasing gradually from top to bottom.The soil CO_2 concentration has a peak in the spring warming,with a short dropping afterwards,and then rises with summer melting.But the time of rising has difference,which may be caused by the dissimilarity of water condition.The CO_2 concentration in soil profile has significant correlativity with the total organic carbon(TOC),the heavy form of organic carbon(HFOC),the light form of organic carbon(LFOC),carbon in debris,water-deliquescent organic carbon(WDOC),the microbe carbon(MB-C) and the soil water(0~100 cm).The ranges of CO_2 concentration changed successively from 1052 to 3050 mL·m~-3 in Cab-Gel-Sandic Entisols,from 3425 to 39144 mL·m~-3 in Cab-Mat-Cryic Cambisols and from 984 to 12250 mL·m~-3 in Cab-Hap-Cryic Cambisols.These are larger than the range of CO_2 concentration in Chinese Loutu soil and the soil under alpine grassland in Wudaoliang region of the Tibetan Plateau,and differ from the range of CO_2 concentration in soil of farmland and grassland that has been reported.With global warming,the CO_2 concentration in permafrost active layer will change the CO_2 concentration of atmosphere,to which more attention should be pay.