Abstract: The present invention provides a work piece chuck of manipulator in the field of mechanical technology. The chuck comprises a chuck sleeve and an ejector pin set within the chuck sleeve. An elastic clamping element is provided at the front end of the chuck sleeve. The ejector pin could move between a first position and a second position along the axial direction of the chuck sleeve. When the ejector pin is in the first position, the outer circumference of the ejector pin extrudes the clamping element to distort and expand outward to form an expansion state. When the ejector pin is in the second position, the outer circumference of the ejector pin is out of contact with the clamping element to restore the clamping element. The chuck has a number of advantages including firm connection, high reliability and high use value.