To　reduce　the　computational　complexity　of　High　Efficiency　Video　Coding　(HEVC),　this　paper　proposed　an　adaptive　quad-tree　complexity　control　mechanism.　The　proposed　mechanism　first　defines　similar　region　flag　(SRF)　to　distinguish　between　similar　region　and　non-similar　region.　Then,　two　algorithms,　similar　region　depth　range　prediction　algorithm　and　non-similar　region　depth　range　prediction　algorithm,　are　proposed.　The　similar　region　depth　range　prediction　algorithm　estimates　the　feature　of　similar　region　based　on　coding　unit　(CU)　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　depth　correlation　coefficient　(DCC),　which　is　calculated　based　on　scene　content　change.　Experimental　results　show　that　the　pro-posed　mechanism　can　reduce　computational　complexity　by　28.17%　on　average　with　0.75%　Bjontegaard　delta　bit　rate　(BDBR)　increase　and　0.03dB　Bjontegaard　delta　peak　signal-to-noise　rate　(BDPSNR)　drop　under　random　access　(RA)　con-figuration.　For　low　delay　(LD)　configuration,　it　can　reduce　complexity　by　32.99%　with　1.98%　BDBR　increase　and　0.06dB　BDPSNR　drop　penalty.　The　proposed　mechanism　is　expected　to　be　applied　in　the　real-time　environments.　©　2018　APSIPA　organization.