We　study　a　partner　selection　problem　for　virtual　manufacturing　enterprises　facing　an　uncertain　environment.　We　propose　a　new　method　of　using　the　grey　system　theory　to　account　for　uncertainties　in　a　project＇s　start　time,　completion　time,　transportation　time,　as　well　as　cost.　We　first　develop　the　concepts　of　delivery　time　agreement　index　and　cost　agreement　index,　and　then　formulate　a　multi-objective　partner　selection　problem　that　maximizes　the　minimum　delivery　time　agreement　index,　the　average　delivery　time　agreement　index　and　the　cost　agreement　index.　A　chaotic　particle　swarm　optimization　(CPSO)　algorithm　is　developed.　Extensive　computational　results　show　that　the　proposed　CPSO　method　outperforms　the　standard　PSO　in　providing　quality　solutions　more　reliably.