Good quality polyclonal antibody against Microcystin-LR (MC-LR) was obtained from the New Zealand rabbit immunized with the homemade complete antigen BSA-MC-LR. Indirect ELISA shows the titer of this antibody is more than 1.5 x 10(5); Indirect competitive ELISA immobilized the coating antigen OVA-MC-LR was adapted to detect MCs, the calibration curve shows that the detection lower limit is 10 ng/L, and the range of quantitative detection was between 30 ng/L to 3 microg/L, with a good linearity, which will well potentially suit for sensitive analysis for MC-LR in drinking as well as surface water samples.