The　entry　into　force　of　the　Regional　Comprehensive　Economic　Partnership　(RCEP)　on　January　1st,　2022　marked　the　official　launch　of　the　world＇s　largest　free　trade　area.　The　RCEP　agreement　will　gradually　release　its　strengths　to　the　regional　trade　development　and　finally　become　one　of　the　most　important　economic　growth　polarities.　In　this　article,　the　complex　network　theory　was　introduced　in　the　analysis　of　regional　trade　patterns　and　the　investigation　of　trade　relationformation　mechanisms.　Based　on　the　RCEP　agreement,　we　constructed　the　manufacturing　trade　networks　at　both　national　and　industrial　levels,　meanwhile,　we　explored　the　node　and　network　characteristics　combining　with　centrality,　density,　reciprocity,　and　distance　indicators.　Furthermore,　by　using　the　significance　testing　of　the　three-node　motifs,　we　recognized　the　main　trade　patterns　of　the　RCEP　manufacturing　trade.　Finally,　we　established　the　exponential　random　graph　model(ERGM)　and　performed　an　empirical　analysis　to　conduct　the　formation　mechanisms　of　the　RCEP　manufacturing　trade　networks.　The　results　provided　that　the　integrated　trade　pattern　had　a　strong　positive　effect　on　the　relation　formation,　while　the　imbalanced　trade　pattern　was　not　easy　to　form　the　trading　relationship.