The invention discloses an active air-floatation support device which comprises an air-floatation support body, an air-film active adjustment unit, a support body detecting unit and a drive control unit, wherein the support body detecting unit measures the state of air-floatation support, the drive control unit generates a control signal according to a detection signal to drive and control the air-film active adjustment unit to generate an active role so as to dynamically adjust the air film form of an air-floatation support surface, thereby dynamically adjusting the pressure distribution of air film gaps of the air-floatation support device, and improving the dynamic stiffness characteristic of air-floatation support. According to the active air-floatation support device, the dynamic stiffness characteristic of air-floatation support can be significantly increased, and the purpose of stabilizing air-floatation support is achieved. In addition, the active air-floatation support device also has the characteristics of compact structure, convenience in control and high precision, thus being especially suitable for occasions of ultra-precision machining or with high-speed spindles with a high requirement on support dynamic stiffness.