The invention relates to a visualization method and device for a phase equilibrium dynamic state of a seabed hydrate exploitation process. The method comprises the steps that the device is in communication with a temperature-pressure instrument used for detecting the temperature value and pressure value of a hydrate reservoir to obtain the temperature value and the pressure value; and the temperature value and the pressure value are projected into a preset hydrate phase diagram according to the time order formed by the temperature value and the pressure value to make the temperature value andthe pressure value be displayed in the hydrate phase diagram in a data point form. By means of the method and device, the problem that whether the temperature value and the pressure value are in a hydrate dissociation state or a stable range cannot be directly judged can be solved.