The utility model relates to a visual simulation test device for a natural gas hydrate. The device comprises a high-temperature and low-temperature test box, a high-pressure reaction kettle arranged in the high-temperature and low-temperature test box, a charge system connected with a charge opening of the high-pressure reaction kettle, a gas boosting system connected with a gas inlet of the high-pressure reaction kettle, a separation system connected with a gas outlet of the high-pressure reaction kettle, an imaging system arranged at the upper end of the high-pressure reaction kettle, a magnetic stirring system arranged in the high-pressure reaction kettle, and a data acquisition and processing system used for monitoring the temperature and the pressure in the high-pressure reaction kettle, and monitoring the flow rates at the gas inlet and the gas outlet of the high-pressure reaction kettle. The device disclosed by the utility model is capable of simulating the temperature and pressure conditions of a real ocean deep well, accurately monitoring the temperature and the pressure in the reaction kettle, and monitoring the thermodynamic changes of the hydrate during generation and decomposition by acquiring data by a computer, and thus rheological parameters of a drilling fluid can be relatively accurately measured. The device disclosed by the utility model is simple to operate, high in measurement accuracy, and capable of being widely applied to rheological measurement processes for various drilling fluids.