Based　on　the　Nash　equilibrium　theory　of　Bertrand　game,　energy　harvesting　is　introduced　to　study　the　spectrum　pricing　for　the　primary　user　in　cognitive　radio　system,　a　spectrum　allocation　method　based　on　the　primary　user　pricing　game　model　under　energy　harvesting　is　proposed.　Firstly,　the　energy　of　the　radio-frequency　signals　belonging　to　primary　users　is　collected　and　stored　by　the　relay　secondary　users　to　ensure　that　there　is　enough　energy　to　transmit　the　information.　Then,　a　dynamic　game　is　played　with　the　transmission　power　of　the　primary　users　at　the　channel　price　to　achieve　the　system　profit　maximization.　Finally,　the　secondary　users　purchase　the　free　spectrum　and　transmit　their　own　information.　The　simulation　results　show　that　the　new　scheme　improves　the　overall　profit　and　fairness　of　the　system.　©　2022,　The　Author(s),　under　exclusive　license　to　Springer　Nature　Singapore　Pte　Ltd.