In　heterogeneous　networks　(HetNets),　energy　saving　is　vital　for　a　sustainable　network　development.　Many　techniques,　such　as　spectrum　allocation,　network　planning,　etc.,　are　used　to　improve　the　network　energy　efficiency　(EE).　In　this　paper,　micro　BSs　utilizing　cell　range　expansion　(CRE)　and　spectrum　allocation　are　considered　in　multi-channel　heterogeneous　networks　to　improve　EE.　Hotspot　region　is　assumed　to　be　covered　by　micro　BSs　which　can　ensure　that　the　hotspot　capacity　is　greater　than　the　average　demand　of　hotspot　users.　The　expressions　of　network　energy　efficiency　are　derived　under　shared,　orthogonal　and　hybrid　subchannel　allocation　schemes,　respectively.　Particle　swarm　optimization　(PSO)　algorithm　is　used　to　solve　the　optimal　ratio　of　subchannel　allocation　in　orthogonal　and　hybrid　schemes.　Based　on　the　results　of　the　optimal　analysis,　we　propose　three　service　control　strategies　on　the　basis　of　large-scale　user　behaviors,　i.　e.,　adjust　micro　cell　rang　expansion　(AmCRE),　adjust　micro　BSs　density　(AmBD)　and　adjust　micro　BSs　transmit　power　(AmBTP).　Both　theoretical　and　simulation　results　show　that　using　shared　subchannel　allocation　scheme　in　AmBD　strategies　can　obtain　maximal　EE　with　a　very　small　area　ratio.　Using　orthogonal　subchannel　allocation　scheme　in　AmCRE　strategies　can　obtain　maximal　EE　when　area　ratio　is　larger.　Using　hybrid　subchannel　allocation　scheme　in　AmCRE　strategies　can　obtain　maximal　EE　when　area　ratio　is　large　enough.　No　matter　which　service　control　strategy　is　used,　orthogonal　spectrum　scheme　can　obtain　the　maximal　hotspot　user　rates.