The invention discloses a cover assembly, a shell assembly, a shell assembly processing method and a mobile terminal. The cover assembly comprises a circuit board, a front camera module, a plastic cover and a reinforcing plate, wherein the front camera module comprises an image sensor, and the image sensor is arranged on the circuit board; the plastic cover is located at one side, away from the front camera module, of the circuit board; and the reinforcing plate is arranged on the surface of one side, facing the front camera module, of the plastic cover and is arranged correspondingly to the front camera module. According to the cover assembly of the invention, when the plastic cover is impacted, the reinforcing plate plays a role of reinforcement, the deformation generated by the plastic cover can be greatly reduced, the plastic cover can be prevented from being impacted and deformed to a certain degree, the impact force can be prevented from being transferred to the image sensor, reliable protection on the image sensor is further realized, and failure of the front camera module is prevented.