Abstract: Bacillus amyloliquefaciens LJ1 is a bacterium isolated from soil sample which showed good activity against melon powdery mildew.To identify the safety of LJ1 to animals and human beings,the acute toxicity of fermentation broth of LJ1 to rodents was tested,and the content of aspartate aminotransferase (AST),alanine aminotransferase (ALT),alkaline phosphatase (ALP) as well as 6 hemogram indexes in treated mice were detected.The results showed that LJ1 has little toxicity on mice by stomach toxicity tests and rats by skin toxicity tests(LD50>4 640 mg/kg);the content of AST,ALT and ALP in serum and the number of white blood cell,red blood cell and hemoglobin in blood of mice increased with significant difference (PP<0.05) 14 days after treatment.The results suggested that the fermentation broth of LJ1 has some side effect on the viscera function of mice at preliminary stage,but that will be restored 14 days later.Therefore,it could be deduced that LJ1 is safe to animals and has potential in developing as biocontrol agent.