A fastening assembly includes a fastening member, a locking member engaged with the fastening member, and an elastic member sleeved on the fastening member. The fastening member forms an arc resisting sidewall. The elastic member includes a main body and a plurality of elastic strips extending from a same side of the main body and spaced from each other. Each elastic strip gradually closes to an center axis of the main body along the direction of away from the main body. Each elastic strip forms an arc protrusion towards the center axis of the main body on an inner wall. The arc protrusion matches with the resisting sidewall.