Aiming at the problem of cognitive wireless network energy efficiency under underlay spectrum sharing mode，a double improved particle swarm optimization algorithm（DIPSO） for power control was proposed. The optimization of network energy efficiency was realized by recognizing the transmitted power of users under the condition of minimizing constraints. In the simulation process，under the circumstance of considering channel fading and noise interference，the fuction of network energy efficiency and relevant constraints were constructed on the premise where the normal communication of main users was not affected，the basic communication of users was guaranteed， and the transmission power of cognitive users in the cognitive wireless network was minimized. The simulation shows that the proposed algorithm can effectively improve the energy efficiency of wireless network.