The invention provides a three-dimensional zero-gravity simulation device combining a knife cam constant-force spring and an air thrust bearing and relates to a three-dimensional zero-gravity simulation device. The three-dimensional zero-gravity simulation device combining the knife cam constant-force spring and the air thrust bearing is to solve a problem that the aircraft microgravity simulationaccuracy is affected by friction, resistance or turbulent flow in the existing space microgravity simulation method and device. An air film can be formed between a plane air foot and an air supporting plate; a housing is arranged on the plane air foot; two horizontal springs are symmetrically arranged on the internal side wall of the housing; one ends of two knife cams are symmetrically arrangedon the internal side wall of the housing through hinging pieces; the other ends or middle parts of the two knife cams are connected with the two horizontal springs through hinges and connecting pieces; a bearing spindle is connected with a roller arm; rollers are respectively arranged at the two ends of the roller arm; the two rollers are respectively in contact with the arch back parts of the twoknife cams; a vertical main spring sleeves the bearing spindle; and the two ends of the vertical main spring respectively prop against the roller arm and a spring partition plate. The three-dimensional zero-gravity simulation device combining the knife cam constant-force spring and the air thrust bearing is applicable to aircraft three-dimensional zero-gravity simulation tests.