The invention relates to the field of mechanical arms and computer vision technology. The binocular vision based object location grabbing method for a mechanical arm includes steps of 1, mounting a binocular vision camera and a mechanical arm; 2, correcting inner parameters of the binocular vision camera; 3, obtaining depth information of a target object; 4, establishing an image planar coordinatesystem and a binocular vision camera coordinate system; 5, calculating the spatial position of the target object in the mechanical arm coordinate system; 6, calculating the grabbing gesture of the mechanical arm; 7, sending control information. Compared with the prior art, the method has advantages that 1, time requirements for real time grabbing can be met since an object recognition method is simple and the calculation load is comparatively low; 2, a problem of operation failure, which occurs when fine difference exists between the gesture of the target object and an ideal gesture, of a mechanism system adopting a traditional demonstration system is avoided.