The　H.264/AVC　video　coding　standard　can　achieve　considerably　higher　coding　efficiency　compared　with　previous　standards.　Unfortunately,　such　excellent　coding　efficiency　comes　with　extremely　high　complex　computations.　In　order　to　reduce　computational　complexity　of　H.264　and　broaden　its　application　domain,　this　paper　proposes　a　novel　fast　intermode　decision　algorithm.　This　algorithm　includes　early　SKIP　mode　detection　and　unnecessary　RDO　computation　exclusion.　Experimental　results　show　that　our　algorithm　can　averagely　reduce　71%　encoding　time　and　1.94%　bitrate　compared　with　the　reference　software　JM11.0　only　with　0.0875dB　PSNR　loss.