Through field sampling and laboratory analysis, the effects of land use patterns on soil structure and fertility of calcareous soil in karst area of Northwest Guangxi were investigated. Based on the long-term observation plots, we selected five common land use patterns, including mowing grassland (CD), native tree species (XT), deciduous orchard (GY), planted pasture (MC) and planted maize (YM). The stability of soil aggregates and the characteristics of organic carbon in the surface (0-10 cm) and sub-surface (10-20 cm) soil of the five land use patterns were analyzed and compared. The results showed that the content of soil mechanical stable aggregates of the five land use patterns all decreased with the decreasing of particle size, and the content of water-stable aggregates decreased first and then increased with the decreasing of particle size. In addition, the soil aggregates measured by both dry and wet sieve methods were dominated by the aggregates that bigger than 1 mm, and their ratio ranged from 67.04% to 90.11% and from 66.83% to 84.65%, respectively. The mean weight diameter (MWD) and geometric mean diameter (GMD) were employed to evaluate the stability of soil aggregates. Under the dry sieve method, MWD and GMD of both surface and subsurface soil followed the order of XT>MC≈GY≈YM>CD. Under the wet sieve method, MWD and GMD were significantly (P<0.05) different in surface soil, which were relatively higher in XT and MC, and relatively lower in CD and YM. The total soil organic carbon content was higher in surface soil than that in sub-surface soil, and it was significantly (P<0.05) higher in MC, CD and XT than those in GY and YM in surface soil, but only relatively higher in sub-surface soil in CD. The organic carbon content of soil aggregates at all levels was similar to the total soil organic carbon content under each land use patterns. In addition, the contribution rate of organic carbon of aggregates generally decreased with the decreasing of aggregated size under different land use patterns. The stability of soil aggregates and the organic carbon content were relatively higher in XT and MC. The results of this study could provide theoretical support for the adjustment of land use structure in this area.