Abstract: Paenibacillus polymyxa is a kind of biocontrol bacterium which could be used for pathogenic fungi diseases controlling. In the present study, the control effect of P. polymyxa DN-1 on rice sheath blight disease was tested for the first time by the means of fungistatic rate determination, pot experiment, and field efficacy test. The result showed that the fungistatic rate against rice sheath blight in the laboratory experiment and the pot experiment were 62.21%-90.54% and 46.19%-77.11% respectively, when the final concentration of P. polymyxa is 0.5-12 billion spores/L. The field control effect reached 43.43%-75.70%, 59.01%-79.64% in 2013, 50.72%-77.26%, 53.65%-77.29% in 2014, after treatment with P. polymyxa for 12 or 24 days. The field control effect of P. polymyxa at final concentration (12 billion spores/L) was equal to validamycin A at 60 g.a.i/hm² concentration, however, the field control effect of P. polymyxa was much lower than that of thifluzamide at 60 g.a.i/hm² concentration.