Abstract: Artificial plantations were set up by irrigating saline ground water (salt content 4～5 g/ L ) in extremely arid areas in the center of Taklimakan Desert . Soil microorganisms were detected in the drift sand dunes and afforestation plots in March and J une 1998. The result showed that : 1) after the establishment of artificial vegetation , the quantity of microorganisms increased greatly with ages ; 2) soil microbial taxa varied with plant species in the plots of same age ; 3) bacteria were predominant , accounting for 90 % of the total , actinomyces the next and fungi the least ; and 4) there are more microorganisms in the topsoil (0～10 cm deep) of afforested sand dunes than in the subsoil layers (10～50 cm deep) . The changes in quantities of soil microorganisms showed that the drift sand was developing into more fertilized soil.