In　this　paper,　the　energy-efficient　power　control　problem　in　cognitive　radio　(CR)　networks　is　studied　not　only　to　provide　energy-efficient　transmission,　but　also　to　guarantee　the　normal　operation　of　primary　users　(PUs).　Moreover,　the　static　energy-efficient　power　control　(SEPC)　algorithm　is　proposed　in　static　scenario　to　maximize　the　capacity　of　secondary　users　(SUs)　and　to　reduce　the　power　consumption　according　to　the　interference　from　PU　to　SU.　Furthermore,　based　on　the　analysis　of　PU＇s　dynamic　feature　with　Markov　chain　and　SEPC　algorithm,　the　dynamic　energy-efficient　power　control　(DEPC)　algorithm　is　proposed　taking　into　account　the　probability　of　detection　and　false　alarm　caused　by　sensing　errors.　Extensive　simulation　results　show　that　the　performance　of　the　proposed　algorithms　is　significantly　improved　compared　with　the　existing　algorithm.　©　by　HIGH　TECHNOLOGY　LETTERS　PRESS.