In the present paper, a quantitative linear model betweena series of concentrations of E. coliO157 : H7 and counts by BPCL ultra weak luminescence analyzer was built up. And the influences of four different buffers with the same pH (pH = 7.4), Tris-HCl, PBS, KH2PO4-NaOH and Na2 HPO4-C6H8O7, and five different chemical substances with the same mass concentration (10 g x L), NaCl, KCl, NaOH, MgCl2 and NaH2PO4 on ATP bioluminescence were compared. The results showed that Tris-HCl was a suitable buffer for dilution, since it could distinguish well between different concentrations and had the lowest background signals. And MgCl2 could intensify luminescence distinctly, while the other four chemical substances decreased luminescence, of which NaOH decreased luminescence most obviously. Moreover, ATP bioluminescence was correlated well with conventional culture methods (r = 0.96), and the detection limit was 10(3) cells x mL(-1).