Abstract: An reverse phase high performance liquid chromatography (RP-HPLC) assay coupled with electrochemical detection (ECD) for systematically measuring epinephrine, norepinephrine, epinephrine sulfonate and adrenochrome in lidocaine epinephrine injection was developed. Analyses of epinephrine, norepinephrine and epinephrine sulfonate were conducted in oxidation mode, while adrenochrome was analysed in reduction mode. Chromatographic conditions such as potential, pH and ion-pair reagent content of mobile phase and sensitivity range were optimized. The proposed method was demonstrated strictly. The method shows good linear relationship (R2=0999 9) in the linear concentration range of four analytes. The detection limit of epinephrine, norepinephrine, epinephrine sulfonate and adrenochrome is 027, 050, 020, 50 μg·L-1, respectively, and the recovery of these substances is (10034±062)%, (10016±107)%, (10026±121)%, (9797±072)% (n=9), respectively. The method is fast and simple and showed high sensitivity, precision, selectivity and recovery, and can thus be used as a quality control method for drugs containing epinephrine and related substances.