The invention belongs to the technical field of optomechanical design, and particularly relates to a metal mirror with a heat-dissipating structure, in particular to a heat-dissipating aluminum mirror. The metal mirror with the heat-dissipating structure achieves the purpose of offsetting heat stress by forming a heat-dissipating groove running through an optical supporting structure in the edge of an optical supporting surface of the metal mirror, so that when the temperature of the working environment is raised, the surface accuracy of an optical imaging surface of the metal mirror can still meet a requirement of an optical system.