Soil micro bial biomass carbon (MBC) , microbial biomass nitrogen (MBN) , soil respiration (RS) ,and soil organic matter (SOM) under various landuses including farmland, garden plot, artificial pasture, waste land, shrub land, economic w oodland, and arbor land in the loess hilly-g ully region w ere measured. The relationships among soil microbial biomass, soil respiration, soil organic matter (SOM) , and total nitrogen (TN) w ere studied and the function of soil microbial pro perties as bio-indicators of soil health w as illustrated. In addition, the effects of landuse on soil organic matter w ere evaluated. Results indicate that the content of MBC in topsoil ranges from 84. 14~ 512. 78 mg/ kg; the content of M BN, from 4. 29 to 41. 83 mg/ kg; and the content of RS, from 108. 69 to 235. 71 mg/ kg. The contents of microbial biomass and RS in to psoil are higher in w aste land and arbor land and low er in the farmland. T he content of SOM in topsoil is 0. 510%~ 1. 547% and it is higher in the economic w oodland and arbor land and low er in the farmland, garden plot, and artificial pasture. Its differences are significant in various landuses. Soil microbial biomass and RS are markedly correlated w ith organic matter and total nitrogen and soil micro bial properties can be used to indicate the health of soils. T he conversion of farmland into other landuses results in a remarkable increase in the amo unts of microbial biomass and soil organic matter, especially in topsoil.