The invention relates to a binocular stereovision measuring device and method for the attitude angle of a triaxial air floating platform. The measuring device is composed of two cameras, camera bases, a measuring target, light sources and a computer, wherein the two black and white digital CCD (charge coupled device) cameras are arranged above the triaxial air floating platform and are arranged on the camera bases, the artificial light sources are installed on the neighborhood of the cameras, and the stereoscopic measurement target is installed on an air floating ball bearing platform surface. The method comprises the following steps of: establishing a coordinate system, respectively collecting a digital image of the target through stereoscopic measurement by the two cameras, and transferring the images to the computer; and integrating projection matrixes between the two cameras and the measure target as well as positioning information of a measuring illuminating mark, calculating the three-dimensional coordinate of each marking point in a world coordinate system according to a stereovision measuring theory, and resolving absolute attitude angle information of an air floating ball bearing through coordinate conversion. In the mode, the non-contact, non-disturbance and high-frequency measurement of a triaxial air floating platform can be realized.