Conventional　rate　control　algorithms　allocate　bits　for　every　macroblock　(MB)　without　consider　whether　it　needs　encoding,　and　they　choose　encoding　mode　only　from　the　set　provided　by　H.264/AVC　standard.　While,　according　to　the　human　visual　system　(HVS)　research,　human　eyes　can　only　focus　on　one　area　in　a　frame,　which　is　called　region-of-interest　(ROI).　This　phenomenon　gives　a　chance　to　code　all　MBs　unequally,　especially　for　NROI　MB,　we　may　do　not　need　encoded.　In　this　paper,　a　ROI-based　rate　control　algorithm　for　H.264/AVC　video　coding　is　proposed　to　improve　the　coding　efficiency.　After　the　ROI　segmentation,　the　target　bits　are　unequally　allocated　for　each　MB.　For　non-region-of-interest　(NROI)　MB　coding,　we　proposed　the　Active　MB　Concealment　(AMC)　Mode　in　rate-distortion　optimization　(RDO).　The　AMC　gives　a　tradeoff　between　the　rate　and　distortion　and　improve　the　quality　of　the　ROI　MBs　at　the　cost　of　the　quality　decreasing　of　the　NROI　MBs.　Compared　with　the　conventional　rate　control　algorithms,　the　experimental　results　demonstrate　that　the　proposed　algorithm　gives　the　better　performance　in　terms　of　the　average　peak　signal-to-noise　ratio　(PSNR)　and　the　subjective　evaluations,　and　maintains　the　smoothness　of　video　quality.