The present disclosure discloses a composite hinge assembly, comprising a clamping portion and a rotating shaft portion fixed relative to the clamping portion and extending out of the two ends of the clamping portion. An inner surface of the clamping portion defining a slot, and an outer surface of the clamping portion is a damping layer made of an elastic material. The present disclosure also discloses a tablet computer kit and a multi-functional keypad thereof.