Abstract: The fluorescent complex,Tb(Ⅲ)-Enoxacin-Phenanthroline,was used as a fluorescence probe in the fluorophotometric determination of ATP.It was found that the fluorescence produced by the above mentioned ternary complex was quenched by the presence ATP in an acetate buffer medium of pH 6.7,and that the magnitude of the decrease in fluorescence intensity kept a linear relationship with the concentration of ATP in the range of 0.1 to 10.0 mg·L-1 of ATP with its detection limit as 0.02 mg·L-1 when measured at λex=340 nm and λem=545 nm.In its application to the determination of ATP in drug tablets,RSD was found to be 2.34%,and results of recovery test were in the range of 98.4% to 104.0%.