A composite heat-dissipating module includes a base, at least one fin unit, a stirring unit, and at least two horizontal air-feeding units. The base includes a top face, a bottom face, and a compartment. The bottom face is in contact with an object to be heat-dissipated. A heat-conducting liquid is received in the compartment. The fin unit is mounted on the top face of the base. The fin unit includes a plurality of fins. A heat-dissipating channel is defined between a pair of the fins adjacent to each other. A stirring unit stirs the heat-conducting liquid to circulate the heat-conducting liquid in the compartment. The horizontal air-feeding units are mounted on at least one side of the fin unit. The horizontal air-feeding units provide lateral airflows into the heat-dissipating channels for dissipating heat.