Abstract: 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%.