Abstract:A field experiment was carried out to study the effect of application of different organic materials on soil microbiological properties such as soil microbial biomass and soil fertility in Weibei rainfed highland . The results showed that the organic treatments(T2-T6) improved soil microbiological properties [soil microbial biomass C (MBC& N (MBN)、urease activity, alkaline phosphatase activity] and some nutrient situation（soil total nitrogen、available phosphorus、available potassium and CEC）compared with CK, especially in the mineral fertilizers plus straw compost treatment (T5). As follows, MBC、MBN、urease activity、alkaline phosphatase activity and available phosphorus increased by 41.96%, 54.55%, 19.71%, 7.35%, 63.12% respectively. Both of SMBC&SMBN had positive significant correlation with available phosphorus、CEC, and qMB、urease activity, alkaline phosphatase activity were with a significant correlation to soil total nitrogen、available nitrogen、available potassium. Meanwhile, there were closely correlation between MBC、MBN、qMB with crop yield (the correlation coefficient were 0.85，0.74，0.82 respectively). Consequently, mineral fertilizers plus straw compost treatment have profound significance on enhance soil quality comprehensively in Weibei rainfed highland. Also MBC & MBN could characterize soil fertility and productivity levels for its agreement with soil nutrient condition and crop yield.