Abstract: Changes in functional diversity of soil microbial community under different land use patterns in Tajikistan were investigated in order to provide scientific instructions to develop rational measures for preventing soil degradation and realizesustainable use of resources. By using BIOLOG Eco plate system，seven kinds of typical land use patterns were selected in Khatlon that is the major agriculture region of the country for taking and analyzing soil samples to compare the properties in soil microbial community functional diversity. The results showed that the utilization activity，kind and amount of carbon source used by microbial community under different land use types varied markedly. The AWCD（average well color development) values were changed in the following order: natural grassland’s>irrigated wheat’s>plum tree and cotton intercropping’s>mulch drip irrigation cotton’s>dry land wheat’s>cherry tree and cotton intercropping’s>open furrow irrigation cotton’s. The functional groups were divided into four types according to carbon utilization models of soil microbial community in different land use types. The Principal Component Analysis （PCA） identified 3 principal component factors in relation to carbon sources，explaining 73.9%，9.3% and 7.7% of the variation respectively. Sixteen categories of carbon sources were significantly positively related to the principal component 1（PC1），and carbohydrates，amino acids and derivatives were the main carbon resources separating the 3 principal component factors. The differences of Shannon and McIntosh index values in microbial functional diversity were holistically in an order of  natural grassland>open furrow irrigation cotton>mulch drip irrigation cotton>irrigated wheat>intercropping of plum tree and cotton>dry land wheat>intercropping of cherry tree and cotton，while no significantly different existed for Simpson index in cultivated lands except the natural grassland. It was suggested that soil microbial community functional diversities were quite different under different land use patterns. The carbon utilization efficiency in natural grassland was significantly higher than in the others，and decrease of soil biological properties and biochemical function in the cultivated lands may result in deterioration of soil quality. Also，rational fertilization，irrigation practices and land management could increase the metabolic activity of communities for carbon and improve the functional diversity.

Key words: different land use types, microbial community, BIOLOG, functional diversity, Tajikistan