Internet　of　Things　(IoT)　is　a　key　application　of　future　6G.　However,　it　is　challenging　to　provide　high-quality　wireless　coverage　for　billions　of　IoT　devices　with　limited　Radio　Frequency　(RF)　bandwidth.　Visible　Light　Communication　(VLC)　utilizes　abundant　ultrahigh　bandwidths　as　complement　to　RF　communication.　This　paper　investigates　the　Energy　Efficiency　(EE)　of　a　Simultaneous　Lightwave　Information　and　Power　Transfer　(SLIPT)　enabled　multi-user　VLC　system.　An　EE　maximization　problem　is　formulated　under　constraints　of　Quality　of　Service　(QoS)　requirements　of　energy　harvesting　and　information　rate　at　users,　avoiding　clipping　distortion　by　the　nonlinearity　of　the　LED　and　the　power　budget　at　VLC　transmitter.　To　solve　the　considered　problem,　an　iterative　algorithm　is　proposed　based　on　Dinkelbach　and　successive　convex　approximation　methods　to　optimize　the　beamforming　vectors　and　the　direct　current　offset.　The　convergence　of　the　proposed　algorithm　is　theoretically　proved.　The　impact　of　the　constraint　of　avoiding　clipping　distortion　by　the　nonlinearity　of　the　LED　on　EE　is　discussed.　Simulation　results　verify　the　analysis.　Moreover,　the　impacts　of　QoS　requirements　of　users,　the　power　budget　at　VLC　transmitter　and　the　filed　of　view　of　LED　on　EE　are　illustrated　and　analyzed.　©　2022　Science　Press.　All　rights　reserved.