Abstract: The Rhizosphere microorganism quantity and fungal flora of the healthy and infected CUcumber plants by F ．oxysporum were studied．The results show that the rhizosphere fungi and bacteria quantity of the healthy plants are much higher than those of the infected ones．Quantities of rhizosphere actinomyces of the healthy and infected plants have no obvious difference．8 sorts of rhizosphere fungi emerge in the healthy plant，including 3～4 sorts of common fungi．Domirmant colonies of total iS from 25％ to 56％．Instead．only 2～4 sorts of rhizosphere fungi exist in the infected plant which iS rareand dominate fungi．The domi nant colonies occupy above 88％ of the tota1．which iS proved to he Fusarium oxysporum(Sch1．)f．sp．cucurnerinum．