The invention relates to a natural ventilation salt-bath scaled model experimental device, which is characterized in that: the natural ventilation salt-bath scaled model experimental device is provided with a salt water storage tank, a clear water tank and a high order salt water tank; the high order salt water tank is connected with the salt water storage tank; a model building is arranged in a model building sink arranged in the clear water tank; a dispenser arranged above the model building is communicated with a salt water inlet corresponding to the model building through a brake valve onthe dispenser, and is communicated with the high order salt water tank through a brake valve of a pipe, a flowmeter and a regulating valve; and a built-in submerged pump in a header tank is communicated with the clear water tank. The experimental device can simulate upward movement of hot air under buoyancy driving by using downward movement of salt water under gravity driving in a scale-model test, simulate a temperature field in an actual building by using the density difference generated by the salt water and clear water, and utilize the clear water to compare cold air of the ambient environment and the salt water to compare an internal heat source of a room. If the scaling of corresponding variables in the model building and the actual building is known, the temperature field and the ventilation quantity in the actual building can be predicted through model experiments, so that a simulated result is similar to an actual condition, and the cost is low.