In this study, RP-HPLC with fluorescence detection and Fluorescence spec trum(excitation 277nm and emission 306nm) was used to detect hydroxyl radic al generated by Cu(Ⅱ)-H_2O_2 (Fenton like reaction) system, using a fluorescenc e probe, L-phenylalanine, which could be converted to highly fluorescent L-tyr osine in the presence of -OH. Before and after reaction, the variety of fluores cence intensity reflected the generation of OH. The data of two methods wer e compared. By this, we can conclude that the re...