Microorganisms in permafrost can live in cold environments due to coadapted physicochemical processes in this environment.In this paper,the relation between microbial number and soil physicochemical properties at the headwaters area of the Urumqi River is analyzed by using fluorescence microscopy counting and oligo-culture techniques.In total,20 samples from a 200-cm permafrost core were used as study materials.The study reveals that the number of culturable bacteria has a significantly positive correlation with soil water content,total carbon and total nitrogen concentrations,and a significantly negative correlation with soil pH value.In addition,the ratio of culturable bacteria to total cell number decreases with depths.The results demonstrate that the number ofculturable bacteria in permafrost is closely correlated with soil physicochemical properties and depositional age.