H.264/AVC　is　the　outstanding　and　significant　video　compression　standard　developed　by　ITU-T/ISO/IEC　Joint　Video　Team　(JVT).　Motion　estimation　(ME)　plays　a　key　role　in　H.264/AVC,　it　concerns　greatly　on　computational　complexity　especially　when　using　the　full　search　(FS)　algorithm.　Although　many　fast　ME　algorithms　have　been　proposed　to　reduce　the　huge　calculation　complexity　instead　of　FS,　the　ME　still　can　not　satisfy　the　critical　real-time　application＇s　needs.　In　this　paper,　a　fast　integer　pixel　variable　block　motion　estimation　algorithm　based　on　JVT　which　accepted　UMHexagonS　algorithm　is　presented　for　H.264/AVC　encoder.　With　special　considerations　on　the　motion　activity　of　the　current　macro-block,　several　techniques,　i.e.,　adaptive　search　strategies　have　been　utilized　to　significantly　improve　the　video　coding　performance.　The　simulation　results　analysis　shows　that　the　proposed　algorithm　maintains　an　unnoticeable　quality　loss　in　terms　of　PSNR　on　average　compared　with　FS　and　reduces　nearly　20%　motion　estimation　time　compared　with　UMHaxagonS　while　maintaining　coding　efficiency.