Abstract: To clarity the mode of Ageratum conyzoides root exudates in promoting the biocontrol effect on pomegranate wilt, a laboratory experiment was conducted to examine soil solution of A. conyzoides root exudates on growth of the strain of Bacillus subtilis and the pathogen of Ceratocystis fimbriata. It was showed that soil solution of A. conyzoides root exudates promoted proliferation of B. subtilis. However, no obvious role was observed for root exudates of A. conyzoides in hypha growth of C. fimbriata. The results suggested that the effect of A. conyzoides on controlling pomegranate wilt relied on promoting the growth of B. subtilis, not by influencing the growth of C. fimbriata directly.