The　Rate-Distortion　(RD)　performance　of　High　Efficiency　Video　Coding　(H.265/HEVC)　has　been　greatly　benefited　from　its　hierarchical　prediction　structures,　which　adopt　different　Quantization　parameters　(Qps)　in　Group-of-Pictures　(GOPs)　and　hierarchical　layers.　However,　these　Qps　are　conventionally　fixed　and　unable　to　adapt　to　dynamic　video　contents.　In　this　paper,　we　propose　a　Qp　Cascading　(QPC)　scheme　that　adaptively　allocates　Qps　to　all　GOPs　and　hierarchical　layers　in　Low　Delay　(LD)　and　Low-Delay　P　(LP)　predictions.　Firstly,　we　separate　the　video　frames　by　a　structure　of　virtual-GOP　(vGOP)　and　explore　the　inter-　and　intra-vGOP　RD　dependencies.　Then,　these　dependencies　are　utilized　to　formulate　a　two-stage　Qp　cascading　scheme:　inter-vGOP　quantization　assignment　and　intra-vGOP　QPC.　Comprehensive　experiments　show　that　the　proposed　scheme　greatly　improves　the　coding　performances　of　all　Common　Test　Condition　(CTC)　classes,　which　outperforms　typical　fixed　and　adaptive　QPC　schemes　that　have　been　developed　recently.　©　2017　IEEE.