The invention relates to the field of new techniques of laser processing and vibration aging, in particular to a surface strengthening method for a metal component by vibration-assisted laser shock treatment. According to the method, by combining laser shock strengthening technology with vibration aging treatment, a vibration exciter is used to excite vibration, a sensor picks up vibration, the vibration frequency is controlled to keep the amplitude value within a specified range, laser lap impact strengthening treatment is carried out with the aid of vibration aging treatment so that more serious plastic deformation can be generated on the surface of the metal component, and high-amplitude residual compressive stress is induced in an impact area; meanwhile under the condition that laser beam irradiates the metal surface, vibration further refines or even nanocrystallizes the surface grain, and under the action of the temperature field, vibration reduces the thermal stress field gradient, and thus the residual stress inside the material is uniformized; and the mechanical properties of the metal component are remarkably improved, and the metal surface is strengthened, so that the fatigue life of the metal component is prolonged effectively, and initiation and expansion of fatigue cracks are prevented.