The work aims to propose a method to position the pictorial trademark of milk powder cans regarding the problem that the uncertainty between the high cover lock of the milk powder package and the pictorial trademark of the can will affect the product aesthetics and brand awareness. First of all, the coordinates of a pair of edge points on the can edge in camera coordinate system were obtained through the perspective projection transformation model, and the equation of sectional circle of the cans was determined in camera coordinate system combined with the principle of lines-of-sight intersection. After that, the central coordinate of a significant pattern on the can was extracted by a temple matching algorithm. Hence, a line of sight between the central coordinate and the camera optical center was obtained. Then, the cross point was calculated based on the simultaneous equation of the straight line and sectional circle. The cross point indicated the position of center point of significant pattern on the sectional circle. As the relative position between the significant pattern and the pictorial trademark was known, the central coordinate of pictorial trademark could be indirectly obtained based on the central coordinate of the significant pattern. The proposed method was able to quickly measure the pictorial trademark of the cans with an accuracy up to ±1°. The proposed method can measure the trademark area of the cans online quickly and accurately.