The study with traditional dilution plate method and BIOLOG ECO system indicated that under wheat and soybean stubbles, the amounts of soil fungi, bacteria and actinomyces in cucumber field increased, while that of Fusarium oxysporum f. sp. cucumerinum decreased (P <0.05). The Shannon-Wiener index, evenness index, Simpson index, and McIntosh index of soil microbial communities as well as soil microbial biomass C increased (P <0.05), basal respiration and metabolic quotient qCO2 decreased (P <0.05), and soil microbe's sole-carbon-source utilization enhanced. In addition, the contents of soil available P and K and the cucumber yields were also increased markedly. All of these illustrated that wheat and soybean stubbles improved the ecological environment of soil microbes.