Abstract: In order to understand the nematicidal mechanism of Beauveria bassiana against Meloidogyne incognita, the changes of physiological indexes of M.incognita second-stage juveniles (J2), including J2 locomotory behavior (mobile frequency), respiratory intensity, osmotic pressure of body fluid, total sugar content, soluble protein content and acetylcholinesterase activity etc, were detected after treatment with secondary metabolites of B.bassiana Snef23. The results showed that the secondary metabolites of B.bassiana Snef23 significantly reduced the mobile frequency and respiration intensity of M.incognita J2, inhibited the activity of acetylcholinesterase, increased the osmotic pressure of J2 body, interfered with the sugar and soluble protein metabolism of J2, which would lead to lethal effect on M.incognita. The results of present study provided theoretical data for elucidation of the nematicidal mechanism of B.bassiana Snef23, as well as for the prevention and control of plant nematode diseases by using B.bassiana and other nature productions in the future.