The invention relates to an agile satellite on-orbit image quality adjustment method and a universal device, and belongs to the technical field of agile satellite imaging. According to the method andthe device, through a plurality of times of focusing in a certain step length for an agile satellite load front-end optical system in a focusing interval and through determination of an optimum focalplane position by utilizing an evaluation function, autonomous focusing of on-orbit image quality of an agile satellite is achieved; and after autonomous focusing is finished, an image after focusingis acquired again, a drift angle is calculated, and an image plane of the agile satellite load front-end optical system is adjusted according to the drift angle, thus achieving autonomous drift adjustment of on-orbit image quality of the agile satellite. Through a plurality of times of image taking at stable moments of an agile satellite platform, satellite autonomous focusing and drift adjustmentcan be achieved at the same time. Information of the optimum focal plane position and the drift angle is acquired through an image calculation manner more conveniently, and on-orbit image quality adjustment of the agile satellite is achieved, thus avoiding traditional complex adjustment manners, and providing a guarantee for acquisition of high-resolution remove sensing images.