The effects of subsurface drip irrigation scheduling on microbial activity and functional diversity in rhizosphere of cucumber in solar greenhouse were studied in this paper. The results showed that the soil microbial biomass C and N, basal respiration, metabolic quotient and values of AWCD, Shannon and McIntosh indexes were increased at first and then decreased with the increase of irrigation water amount. The values of microbial C and N, basal respiration and metabolic quotient in I₂ treatments were significantly higher than those in I₁ treatments at the 0.8E_p irrigation level. The numbers of bacteria, actinomyces and nitrogenfixing bacteria, and the activities of
urease, phosphatase, sucrase, catalase and polyhenoloxidase were significantly higher in the 0.8E_p treatment than in the other treatments. The numbers of bacteria and nitrogenfixing bacteria, the activities of urease, phosphatase and sucrase in I₂ treatments were significantly higher than in I₁ treatment, the actinomyces number and activities of catalase and polyhenoloxidase had no significant difference between I₁ and I₂ treatments, however, the fungi number in I₂ treatments were significantly lower than in I₁ treaments at the 0.8E_p irrigation level. The microbial activity and functional diversity in rhizosphere of cucumber were strengthened in the I₂0.8E_p treatment, meanwhile, the soil microflora was improved and the soil enzymes activities were enhanced, therefore, the cucumber growth was promoted as well.