The BCS theory explains the superconducting properties of Class I conventional metal and alloy superconductors, but it cannot interpret the superconducting phenomenon of Class II unconventional superconductors. The BCS theory violates Coulomb’s law and Heisenberg’s uncertainty principle, and its microscopic mechanism of electron-phonon coupling is essentially wrong. Based on the elastic collision theory of Newtonian classical mechanics, this paper proposes the electron elastic collision superconductivity theory, which reveals that the microscopic mechanism of superconducting states is that the free electrons in a current-carrying wire only undergo complete elastic collisions with the atomic lattices, and the current-carrying wire shows zero-resistance superconducting states. The electron elastic collision superconductivity theory proposes the superconducting state free electron critical speed VC, and theoretically derives the formula for calculating the critical temperature TC: 2 ΔE = 3.7 kB TC. The critical kinetic energy ΔE of the free electron is equal to the minimum phonon energy hγ of the atomic lattice vibration. There is no heat conduction diffusion in the superconducting current-carrying wires, so there are no phonons in the superconductors. The electron elastic collision superconductivity theory interprets the microscopic mechanism of the superconducting state critical temperature TC, the critical magnetic field HC, the critical current density jC, the superconducting state energy gap and the high-pressure superconductor. Unlike Class I conventional superconductors, Class II unconventional superconductors have anisotropic lattices. There are different critical speeds VC, different critical temperatures TC and different critical magnetic fields HC in different directions. Based on the Electron elastic collision superconductivity theory, it is feasible to achieve a zero-resistance superconducting state at normal temperature. Unconventional two-dimensional thin film superconductors and one-dimensional carbon fiber superconductors are the development direction of normal temperature superconductors.