A hundred years ago, Planck and Einstein and others created quantum theories or quantum mechanics while they explained the photoelectric effect. Planck and Einstein empirically obtained a statistical relationship between the energy of light quantum and the frequency of light but have not studied the physical process and essence of the photoelectric effect, so some photoelectric phenomena are difficult to be explained by existing quantum mechanics currently. In this paper, a dynamical process of orthogonal interaction between a photon and an electron to form a new state of matter in photoelectric effect experiments is studied so finding that the Planck constant is a product value of the mass, length, and velocity of a high-energy particle. The dynamics of the orthogonal collision of matter (particles) can not only give the physical process and essence of the photoelectric effect, but also have great significance for the further development of quantum mechanics. It can physically explain phenomena such as wave-particle duality and quantum entanglement in the motion of high-energy particles. Its prospects can be widely used in cosmic physics, macro physics, and micro physics.