For　video　quality　assessment　and　video　information　security,　this　paper　presents　a　novel　method　for　motion　salient　region　(MSR)　detection　by　analyzing　the　spatial-temporal　information　of　region-of-non-interest　(RONI).　The　RONI　is　defined,　and　the　motion　salient　regions　can　be　considered　as　its　complements.　Experimental　results　show　that　the　scheme　can　effectively　detect　the　motion　salient　region,　especially　to　the　videos　with　complicated　camera　motion　and　the　accuracy　rate　can　be　93%.