Dissipative particle dynamics simulations are carried out to study the microphase separation of comb-like block copolymer in two dimensions. By systematically varying the side chain lengths and the repulsion strength between the two components,we find various morphologies. For comparison,the linear and star-like block copolymers are also studied in the simulations. The results reveal the main factors that affect the microphase separation of comb-like block copolymers in melts.