A visual computing model based on attention mechanism with the following characters is proposed in this paper.First

it imitates the characteristic of zoom-lens

eye movement and head movement of human vision system. Second

the retina character is modeled by a new nonuniform sampling method with changeable structure. Third

the bottom-up process driven by data and top-down process driven by knowledge are combined. A novel knowledge representation method and a fixation movement controlling mechanism based on depth first search tree are proposed as well.