Abstract: In this paper,we study current robot grippers and hand-mechanisms problems,and put forward four functional requirements of a new robot hand-mechanism.Onthe basis of two fundamental conceptions——mobility and connectivity of the mechanism,we get two conditions which must be satisfied by a robot hand-mechanism.And finally,we select from many feasible schemes a certain kind of five-finger-mechanism,namely,A3-A3-A3-C1-C1,as the new multi-functional hand-mechanism,which is a simpleand practical mechanism with minimum degrees of freedom.