The paper concerns with the visual illusion strength for the static and dynamic figures which are generated on computer CRT. The Vertical-Horizontal, Ponzo, and Muller-Lyer illusion are studied under various conditions of type, size, and background angle of figure. And the results are obtained through the Multivariate Analysis of Variance (MANOVA). This paper concludes that the size and background angle of figure generally effect on the visual illusion, and there is a significant difference between figure types. These results can be applied to eliminate the visual illusion in real design. Keywods: Visual illusion strength; Static and dynamic figure; Vertical-horizontal illusion; Ponzo illusion;Muller-Lyer illusion