Abstract: The effects of bio-compound fertilizer on soil microorganism were assessed using plate count method, CHCl3 fumigation-extraction method and Biolog micro-plate technique on potted corn plants in greenhouses. Results showed that bio-compound fertilizer treatment increased the number of bacteria, fungi and antinomies in soil. The fertilizer treatment also increased the amount of C and N in soil microbial biomass, and the capacity to utilize single carbon substrate, it also increased biodiversity and evenness of soil microbial community. Therefore, the bio-compound fertilizer treatment was beneficial to the diversity and function of soil microbial community; it also promoted the stability of soil ecological system and improved ecological functions of soil microbial community.