Soil microbes in the root zones of cucumber were investigated.Three major micro-groups,major functional groups and the soil microbial biomass carbon(MBC) were addressed with various fertilization treatments.The study aimed to further understand the effects of different fertilization on microbial composition and MBC in cucumber root zone soil.The results showed that the fertilizer could be ranked in a descending order in terms of the total amount of soil bacteria,fungi and actinomycetes of the root zone as following: compost50% compost+50% chemical fertilizercommon fertilizerordinary organic fertilizerCK.For the diversity,soil actinomycetes of the compost treatment had the highest Shannon-Weiner index and the greatest amount of soil ammonifying bacteria,nitrogen-fixing bacteria and cellulose decomposition bacteria,while the treatment with 50% compost+50% chemical fertilizer had the greatest amount of soil nitrifying bacteria.Furthermore,soil MBC increased after applying both fertilizers containing compost.These results indicated that compost fertilizer could increase the amount and diversity of soil micro-organisms and subsequently improve the soil fertility.