Abstract: This study established an available analysis method for the detection of microcystin LR in drinking water. The mobile phase acidity, elution rate and column temperature were optimized in this method. 0.04% TFA/acetonitrile (63 37) was chosen as the mobile phase, elution time was 7 min. The method was gentle, fast, economical, available etc. Through the detection and analysis of microcystin LR in a typical reservoir of Guangdong province, we found that this method was reliable, accurate, sensitive, and the recovery was 88%, the lowest detection limit was 0.05 g/L.