In this paper,the biological control effect of fermentation of Streptomyces roseoflavus Men-myco-93-63based on mushroom bran was studied and evaluated.The controlling effects of fermentation of biocontrol bacteria on vegetable root knot nematode and its effects on promoting effect and fruit quality of plants were evaluated in the pot experiment of cucumber in greenhouse and field test of watermelon and cowpea in Beijing suburb field.The results showed that in the greenhouse efficacy test,the control effect of Streptomyces roseoflavus fermentation on cucumber root knot nematode disease was 29.41%.In the field efficacy test,the control effect of Streptomyces roseoflavus fermentation on watermelon root-knot nematode disease was 14.29%,and that of cowpea root-knot nematode disease was 14.81%.After the application of Streptomyces roseoflavus mushroom bran fermentation in the field,the growth of watermelon plants was obviously promoted.The single fruit weight of melon was significantly different from that of the control,and the yield of cowpea was increased by 18.03% and 10.20% compared with the control.This paper provides an important reference basis for the research and application of Streptomyces roseoflavus Men-myco-93-63microbial fertilizer.