With　the　increasing　application　of　unmanned　aerial　vehicles　(UAVs),　UAV-based　base　stations　(BS)　have　been　widely　used.　When　there　is　no　ground　BS　or　BSs　being　out　of　service,　such　as　mountainous　areas,　isolated　islands　and　disaster　areas,　UAV-based　networks　may　be　rapidly　deployed　for　communications.　In　this　paper,　we　propose　a　framework　of　power　control　and　channel　allocation　for　an　underlying　device-to-device　(D2D)　communication　in　UAV-based　networks.　The　objective　of　this　study　is　to　maximize　the　energy　efficiency　of　D2D　pairs　while　ensuring　the　quality　of　service　of　networks.　Four　kinds　of　interference　scenarios　in　the　system　are　considered,　including　intra-cell　interference　and　inter-cell　interference　generated　by　cellular　users　and　D2D　transmitters,　respectively.　In　addition,　we　assign　UAVs　to　D2D　pairs　and　formulate　the　uplink　power　control　and　channel　allocation　problem.　Then,　the　quantity-weight　adaptive　salp　swarm　algorithm　(QWASSA)　is　proposed,　which　adopts　dynamic　leader-follower　numbers　and　positions　update　form.　Finally,　the　performance　of　the　QWASSA　is　evaluated　by　simulations,　and　results　show　that　the　QWASSA　has　excellent　global　searching　ability　and　local　mining　ability,　which　is　not　only　superior　to　other　benchmark　schemes　but　also　close　to　the　optimal　performance　of　D2D　pairs　in　terms　of　energy　efficiency.　©　2021　IEEE.