The　residual　signal　gained　after　motion　estimation　needs　to　be　transformed　and　quantized　prior　to　entropy　coding　in　H.264/AVC.　In　many　cases,　especially　in　low　bitrate　situation,　the　probability　that　obtain　all　zero　quantized　coefficients　block　(AZB)　is　high.　In　this　paper,　we　study　the　characteristics　of　4x4　integer　transform　first,　and　then　we　use　the　divide　and　rule　strategy　to　inverse　the　formulae　of　integer　transform　and　quantization.　By　this　way,　we　get　a　new　sufficient　condition　for　AZB　detection.　The　experiment　results　show　that　our　algorithm　can　find　out　more　AZBs　compared　with　existing　methods　without　any　loss　and　save　more　computations　at　the　same　time.