Abstract: Seven years experiment on the effects of bio-organic fertilization,including 15t/hm²·a and 7.5t/hm²·a vermicompost(EM compost,EM chook manure and traditional vermicompost),and chemical fertilizer on soil fertility and microbial biomass carbon was conducted at the Quzhou Station of China Agricultural University.The results show enhancement in soil fertility and improvement in soil physical-chemical properties under long-term application of EM compost or traditional vermicompost.Soil pH values gradually decline when applied EM compost or traditional vermicompost increases,but soil organic matter,total N,alkali-hydrolyzable N,available P,available K and soil microbial biomass carbon increase;while significant positive correlations are observed between them and the used amount of fertilize.Chemical fertilizer enhances soil organic matter,total N and available nutrient to a certain extent.The different fertilizers are ranked according to their effects on soil fertility and microbial biomass carbon as follows:control＜chemical fertilizer＜traditional vermicompost＜EM compost.Significant positive correlations are observed between soil microbial biomass carbon and soil organic matter,total N,alkali-hydrolyzable N,available P and available K;indicating that microbial biomass carbon could be a biological indicator in soil quality evaluation.