Abstract: Cucumber powdery mildew is one important diseases threatening to the facility cultivation of cucumber, biological agents application to control cucumber powdery mildew is significantly critical to meet organic agriculture standard (GB/T 19630——2011) requirements in the actual production. This study compared the effect of bacillus subtilis wettable powder (1 billion cfu/g) and amino-sugars for powdery mildew control in organic cucumber planting. Results showed that, continuous spraying 200 times bacillus subtilis wettable powder or 700 times amino-sugars could better control the occurrence of powdery mildew when the cucumber powdery mildew disease was lighter (disease index less than 18.19). And the control effects reached 87.2%- 90.7% and 52.5%- 91.5% respectively. It was advised that before the organic cucumber powdery mildew happened or the disease index less than 10 use biological agents to control organic cucumber powdery mildew.