Hydrate decomposition is an essential part of hydrate mining and has important research significance. In this paper, hydrate thermal decomposition experiments were carried out in a self-designed high-pressure stirring hydrate reaction system, and the microscopic behaviors of the decomposition were captured by a high-speed camera. The main content of the study is the microscopic morphology of hydrate decomposition. According to the experimental data, three kinds of hydrate particles, including granular, flake, and block hydrate particles, were defined, and their decomposition behaviors were analyzed. Finally, based on the independent physical models of the three hydrate particles, physical model of the hydrate particle flow decomposition was established.