The invention relates to the field of laser impact strengthening devices, in particular to a device and method for laser machining a ball bearing outer rollaway nest. The device comprises a laser, a signal line, a controller, a light spot adjusting unit, a manipulator A, a camera, a lens, a clamp, a manipulator B and a 45-degree total reflection mirror. According to the device, a divergent lens isused for enabling the intensity of the light spot irradiated on the curved rollaway nest to be uniform, the camera is used for monitoring the shape and size of the light spot in real time, and the power density is strictly controlled. The invention provides the method for uniformly machining the curved rollaway nest, the method is less limited by the size of the curved rollaway nest and has the advantage of low equipment manufacturing cost.