Cloud　manufacturing　transforms　scattered　resources　and　capabilities　supplied　by　entity　enterprise　into　integrated　manufacturing　cloud　services,　which　can　be　realized　through　composing　different　services.　A　complete　candidate　service　set　is　the　foundation　of　developing　a　composite　service　with　higher　quality.　In　order　to　improve　QoS　(Quality　of　Service)　of　the　composite　service,　the　correlations　between　services　are　considered　and　then　classified　in　the　whole　composition　process.　However,　considering　the　correlation　in　composition　process　but　ignoring　it　during　matching　process,　such　as　the　existing　methods　about　service　correlation,　will　affect　QoS　of　the　composite　service.　In　this　paper,　an　extended　service　modelling　is　proposed　to　describe　service　correlations,　and　then　a　reservation　algorithm　is　designed　to　reserve　services　with　correlation　in　service　matching　stage　so　as　to　make　the　composite　service　much　better　than　before.　Simulation　results　demonstrate　the　effectiveness　of　our　model　and　algorithm.