Abstract: Fracture formation and particle migration in hydrate reservoir induced by liquid and gas production are common occurred during marine hydrate exploitation, significantly affecting gas production efficiency and sand production characteristic. Exploring its internal law is crucial for ensuring safe and efficient in hydrate exploitation. A visualization device, incorporating visual monitoring and particle image velocimetry to facilitate real-time observation of reservoir behavior during hydrate dissociation, is developed. Dissociation tests at varying depressurization rates and sediment particle sizes is conducted to explore the characteristic of fracture formation induced by gas production and particle migration. Results indicate that hydrate morphology and reservoir structural significantly affect the fracture formation pattern and evolution. Gas produced from the dissociation of hydrate zones tends to gather in occurrence areas, forming gas pockets that promote fracture development. Microfracture-rich zones often experience fracture extension due to gas migration and accumulation, further driving fracture development. As depressurization rate rises, the size and location of fractures developed, vertical inclination of the longest fractures decreases, and the fracture number increases. When the particle size increases, fractures tend to form at great depths while the number decreases. In addition, with a higher depressurization rate, the proportion of high-speed moving particles in the vessel increases significantly. This causes a notable expansion of particle migration zone, and intensifies the disturbance range in hydrate reservoir.