Abstract: On the basis of image information from visual perception,a model integrated with bottom up visual searching and top down semantic determining was proposed,establishing a perception contact between image areas or image blocks and image semantic or image categories．Through the scanning and searching for image areas,the moving eyes simulate the movement of the focus of attention to index and memory the interested content so as to produce association under the driving of task events．The model blends two aspects of visual perception and semantic explanation in image understanding,which conforms to the human cognitive law.

Key words: Visual perception,Image understanding,Semantic association