The invention provides a device and method for detecting barriers through stereoscopic vision. An image collecting module comprises a plurality of cameras which are used for collecting a plurality of raw images, an image processing module is used for detecting the raw images in an edge mode to generate a plurality of edge objects and object information corresponding to the edge objects, an object detecting module can generate the object relative distance corresponding to each edge object according to the object information and matched with the focal distances and the horizontal distances of the cameras, and a group module is used for comparing the object relative distance with the threshold distance. The edge objects are barriers when the relative distance distances of group articles are smaller than the threshold distance. If the images collected by the plurality of cameras of the module and taken by image staff are asynchronous, the device and the method can solve the problems caused by asynchronous image detection to achieve an effect similar to a synchronous system. Thus, the common cheap cameras can be used, and the cost is remarkably saved.