A simple method for oxidative CC bond cleavage of terminal olefins to aldehydes with H₂O₂ catalyzed by copper(II) complex LCu consisted of copper(II) and macrocyclic ligand 5,7,12,14-tetramethyl-1,4,8,11-tetraazacyclotetradeca-4,7,11,14-tetraene (L) was described. This study indicated that the copper(II) complex displayed excellent catalytic ability for the selective oxidation of terminal olefins to aldehydes with high selectivity (S > 90%) in CH₃CN at 30 °C. The possible catalytic reaction mechanism of oxidation of terminal olefins was discussed.