The aqueous two-phase part itioning(A2PP)technique,considered as a useful tool to separate and purify cells, virus,macromolecule,has found extensive application in biochemistry,cytobiology and other relevant fields.However,few reports are so far available on its applicat ion in the field of soil microbiology.This experiment was designed to study components of microbes in red soils with the PEG/Dextran A2PP technique.Results show that soil bacteria were well dispersed after the Dowex resin,sodium cholate,glass beads and soils were mixed into suspension,which was then shaken for 2h at the temperature of 4 e.The separation rate of bacteria ranged between 0.41~0.60 and varied with parent material in the order of sandstone> granite>Q₂ deposits.The experiments demonstrated that A2PP could separate and purify soil bacteria quite well.With the two-phase technique,about 63%~78% of the bacteria in the soil samples were separated and stored in the PEG phase.With the fluorescence microscope technique,most soil bacteria were closely tied with soil clays and organic matter,whereas with the A2PP technique purer bacteria could be obtained.The bacteria extraction rate was in the range of 0.31~0.48,and varied with parent material in the same order of sandstone>granite>Q₂ deposits as was with the separation rate.For the six red soil samples examined,micrococcus and microbacilli were dominant in terms of forms of soil bacteria.