With the continuous progress of robot grasping technology, the application of robots in industrial applications is promoted. However, reliable grasping of any object is still a difficult problem for robot grasping tasks. In this paper, the parallel grabber is studied as the grabber used in robot grabber detection. The grab detection includes the two-dimensional plane grab method and six-degree-of-freedom grab method, in which the former is constrained to grab from one direction. This paper summarizes the development trend of the two methods and analyzes their advantages and disadvantages.