Industrial　wireless　sensor　networks　(IWSNs)　are　the　fundamental　components　in　the　next-generation　factories.　Due　to　massive　heterogeneous　data　generated　from　large-scale　IWSNs,　it　is　still　challenging　to　achieve　predictable,　deterministic,　and　real-time　transmission　scheduling.　In　this　article,　a　framework　of　priority-aware　packet　transmission　scheduling　(PPTS)　in　cluster-based　IWSNs　is　proposed,　where　the　PPTS　strategy,　the　optimization　theory,　and　the　implementation　design　are　systematically　considered.　In　particular,　the　proposed　PPTS　strategy　not　only　minimizes　the　transmission　delay　of　high　priority　packets　but　also　greatly　improves　the　transmission　delay　of　low　priority　packets.　The　optimization　theory　for　end-to-end　priority-aware　scheduling　in　cluster-based　IWSNs　is　formalized,　which　contributes　to　the　optimal　solution　for　multidimensional　network　resources　allocation　and　achieves　the　minimum　of　average　transmission　delay.　Finally,　the　advantages　of　the　PPTS　framework　over　some　existing　solutions　are　demonstrated　by　a　case　study.