1. An eye exercising device, comprising: a carrier, a controller, and two or more than two light-emitting units, wherein each of the light-emitting units is sequentially mounted on the carrier, and the light-emitting unit is electrically connected with the controller, the controller is used to control each of the light-emitting units to operate in a corresponding state at corresponding time according to an eyeball exercise program to generate a moving light spot for human eyes, each of the light-emitting units comprises a light source and a light-extraction module which comprises a light-mixing unit, a light-homogenizing unit, and a light path adjusting unit, the light source is electrically connected to the controller, the light-extraction module is used to adjust dazzling light emitted by the light source such that the dazzling light emitted by the light source and divergently distributed in a three-dimensional space is transformed into a visual guide target with boundaries for human eyes to recognize, brightness at a center of the visual guide target is reduced and the moving light spot with boundaries is generated for instructing eyeballs of the human eyes to do exercising;