The invention discloses a gas film sealing non-contact gas supply device and method of a gas flotation physical simulation platform. A gas guide unit composed of a gas guide block and a gas guide holeis arranged in the center position below a translational motion platform of the gas flotation physical simulation platform in the vertical direction, the gas guide hole is located in the center of the gas guide block, a gas supply unit fixed to a foundation platform is correspondingly arranged below the gas guide unit, a gas supply hole is formed in the center of the gas supply unit, a large-areashallow cavity is formed on the periphery of the gas supply hole, so that when the gas flotation physical simulation platform conducts planar motion, the gas supply hole is located in the range of the shallow cavity all the time, and the finish machining faces of the gas guide unit and the gas supply unit are correspondingly arranged and kept at a distance at the micron scale. Non-contact gas film sealing of the gas flotation physical simulation platform supplied gas and the external ground environment is achieved, gas can be supplied ceaselessly, and the device and method have the beneficialeffects of theoretically infinite experiment time, small simulation environment disturbance torque and the like.