Abstract: Through comparing Human-Human Interaction Interface（ HHII） of CoEditor as a cooperative editing system with Human-Computer Interaction Interface（ HCII） of conventional editing systems，this paper describes the necessity of putting the concept of HHII forward and points out that besides some functions inherited from HCII，HHII has at least three new kinds of functions as follows．（1） HHII provides some functions to organize group people for effectively cooperative work．（2） HHII makes group people know the whole cooperative course．（3） HHII makes every group member have operational feeling of human awareness．