A　next-generation　video　coding　standard　High　Efficiency　Video　Coding　(HEVC)　provides　higher　video　quality　and　lower　compression　bit　rate　but　leads　to　very　high　encoding　complexity,　especially　in　the　quad-tree-based　coding　tree　unit　partitioning　process.　To　reduce　the　computational　complexity　of　HEVC,　in　this　paper,　we　propose　an　adaptive　quad-tree　depth　range　prediction　mechanism.　First,　the　proposed　mechanism　defines　the　similar　region　flag　to　distinguish　between　the　similar　region　and　the　non-similar　region.　Then,　two　algorithms,　the　similar　region　depth　range　prediction　algorithm　and　the　non-similar　region　depth　range　prediction　algorithm,　are　proposed.　The　similar　region　depth　range　prediction　algorithm　estimates　the　features　of　the　similar　region　based　on　the　coding　unit　depth　of　this　region.　The　optimal　depth　of　this　region　can　be　predicted.　The　non-similar　region　depth　range　prediction　algorithm　can　skip　low　probability　tree　nodes　based　on　the　depth　correlation　coefficient,　which　is　calculated　based　on　scene　content　change.　Both　the　similar　region　depth　range　prediction　algorithm　and　the　non-similar　region　depth　range　prediction　algorithm　show　more　than　90%　predictive　accuracy.　Experimental　results　show　that　under　random　access　configuration　and　low　delay　configuration,　the　proposed　mechanism　can　yield　28.17%　and　32.99%　computational　complexity　reduction　with　negligible　rate　distortion　performance　loss,　respectively,　compared　with　HM16.9.　The　results　show　that　the　proposed　mechanism　is　expected　to　be　applied　in　real-time　environments.