We propose a scheme for teleportation of an unknown N-atom state using a two-atom entangled state within a cavity QED and show the feasibility in experiment.Our scheme does not involve the Bell-state measurement and is insensitive to the cavity decay,which is important from the experimental point of view.Another feature of the scheme is that teleporting a N-atom state just requires a small amount of entanglement(i.e.a two-atom entangled state) and less classical bits (two bits).