A combinational chassis featuring heat dissipation comprises a chassis body, a base plane shell, and a first side shell and a second side shell, of which the two sides connect to each other in the same direction of the base plane shell. A heat dissipation device comprises a plurality of heat-sink parts on the outside surface of chassis body. The heat-sink part comprises a raised portion integrally connected to the inside, and a joint portion connected to the outside. The raised portion integrally protrudes outwards from the outside surface. The joint portion geometrically protrudes from the raised portion. A wedge groove is formed near the joint portions where an inlet groove is formed. The inlet groove connects and communicates with the wedge groove. The chassis may be connected vertically in stack and/or connected horizontally for expansion to expand the computer system for preferably flexible application and optimal heat dissipation.