Abstract: In order to evaluate classification status of biocontrol strain S,the inhibition effect on the pathogen of pepper Phytophthora foot rot were studied by using dual culture method and pot experiment, and its biological characteristics were tested too. To determine its classification status, identification experiments were proceeded by morphology and culture feature observation, and physiological and biochemical characteristics determination and 16S rDNA sequences assay. The results showed that strain S had strong inhibitory effect against the pathogen of pepper Phytophthora foot rot. The most optimal temperature for the growth of strain S was 30 ℃. And the most optimal pH was 8.0. Strain S had the nearest evolutionary distance with Paenibacillus sp. by the comparing of 16S rDNA sequences, combining with its results of morphological, culture and biochemical property analysis, it was identified as Paenibacillus polymyxa.