Focus on the requirment of pathogeny detection with high speed, high sensitivity and specificity，a novel method integrated with immunomagnetic separation and adenosine triphosphate(ATP) bioluminescence was developed. Firstly, an immunomagnetic nano probe was prepared by conjugating nano magnetic particles with antibody to capture the aim pathogeny. Sencondly, the pathogeny captured by the nano probe was lysed and the ATP was detected by biolumescence. Escherichia coli(O157H7) samples with concentration of 10～108 CFU/mL(CFU: colony-forming units) were detected. The results show a linear response to the traditional plate count method with a correlation coefficient of 0.934 within 2 h. The reproducibility was also tested by 12 samples with the same concentration of 103 CFU/mL and the coefficient of variabilty is 4.88%.