In cognitive relay networks, secondary users (SU) are encouraged to relay primary users’ (PU) messages for accessing the licensed spectrum to send their own information to secondary receivers (SR). It is a win-win strategy especially when the direct links between primary transmitters (PT) and primary receivers (PR) suffer from severe fading. With the EH ability, energy-limited secondary transmitters (ST) can be strongly stimulated by both the information and energy cooperation between PT and ST, which is investigated in [8]. In that paper, the ST is powered by PT first, and then uses the harvested energy as transmission power to forward PT’s information to PR as well as to send its own information to SR. The SU rate maximization problem is considered subject to the PU rate demand constraint and the energy causality constraint. It has been found that, the SU-PU rate region can be enlarged with the energy cooperation from PT to ST.