A method for sensing a paper skew adapted for a device having a paper feeding mechanism is provided. The device has a feed sensor which is fixed at a start position of paper feeding; and, a position sensor which moves in a direction perpendicular to a direction of paper feeding and passes through a first and a second positions. The first position is the intersection of a moving path of the position sensor and a line. The feed sensor is on the line, and the line is parallel to the direction of paper feeding. The method includes the device having a first distance; moving the position sensor to the second position; feeding a work paper into the device; obtaining a second distance which is a moving distance of the work paper fed; and determining whether the work paper is skewed or not according to the difference between the first and the second distances.