Based on the photon cage theory of the unified light-origin field, free electrons are microscopic steady-state clusters bound by self-locked high-density photons, with definite upper critical thresholds for saturation dissociation and lower critical thresholds for energy dissipation collapse. Relying on the fundamental theories and thought experiments presented in Research on the Measurement of Upper and Lower Critical Energy Thresholds of Free Electrons — Based on the Resonance Dissociation Mechanism of Photon Cages, free electrons can receive continuous and controllable energy supply from coherent resonant lasers. Internal photons accumulate and gain energy continuously. Once the saturation critical threshold is crossed, complete structural dissociation occurs, and all intrinsic mass energy of electrons is directionally released in the form of gamma photons. This microscopic physical mechanism features natural net energy gain. Only low-energy coherent laser photons are input artificially as trigger energy. After particles cross the threshold, massive bound intrinsic mass energy stored inside is released spontaneously, with output energy far exceeding input energy consumption. Compared with traditional nuclear fission and tokamak magnetically confined nuclear fusion, the energy release path of electron photon cage dissociation has subversive theoretical advantages: mild physical conditions, no neutron radiation, no long-lived nuclear waste, extremely easy access to particle raw materials, high safety threshold, and support for modular popularization. This paper only carries out theoretical deduction of physical mechanisms and demonstration of energy feasibility. Technical issues such as industrial trial production, mass equipment manufacturing, engineering implementation and commercial operation fall into the scope of follow-up engineering application research and are not discussed within the theoretical framework of this paper. Theoretical results show that controllable electron dissociation and energy release are inherent cosmic laws of microscopic particles, constituting a low-threshold, high-safety, high-gain physical path with revolutionary potential for new clean energy.