The electrochemical oxidation-reduction processes of adrenaline were studied by multi-mode in situ spectroelectrochemistry involving thin-layer cyclic voltammetry, UV-vis absorption, fluorescence spectroelectrochemistry and electrogenerated chemiluminescence based on a versatile long path-length thin-layer electrochemical cell with a glassy carbon working electrode. It was found that the redox pathways were related to the pH of the solution, the potential window and the oxygen dissolved in the solution. A mechanism was proposed for the redox process under different conditions. Furthermore, the reaction pathway for the electrooxidation of adrenaline was compared with the pathway for the permanganate oxidation of adrenaline, and a possible reason for the fact that the electrooxidation of adrenaline cannot generate chemiluminescence was proposed.