In the present paper, the capture efficiencies of four different proportions of E. coli O157:H7 and immunomagnetic beads (IMB) (1:6.34, 1:12.69, 1:25.38 and 1:30.07) and three different proportions orE. coli O157:H7 and Bacillus suhtilis(0. 3 mL:0.1 mL, 0.2 mL:0.2 mL and 0.1 mL:0. 3 mL)were compared, with the total volume and capacity of IMB remaining constant. It was revealed that the capture efficiency could reach 100% when the proportion of E. coli O157:H7 and IMB was 1:30, meaning that almost all targets E. coli O157:H7 could be captured at 1:30, and that the capture efficiency decreased and then increased with the number of Bacillus subtilis increasing. Moreover, the combination of ATP bioluminescence and IMS was correlated well with conventional culture methods, R^2 = 0. 988 2, and the detection limit was as low as 10^2 CFU · mL^-1.