Self-assembly of symmetric diblock copolymers in confined state has been investigated by means of Monte Carlo simulation method. The symmetric diblock copolymers were confined in two-(parallel walls or circle) or in three-dimensional (spherical pr cylindrical) space. There are interactions between these boundaries and the symmetric diblock polymers. These interactions and boundary shape resulted in the formation of novel self-assemble structures, e.g., strip, circle, core-multishell, and multibarrel-layer structures. Simulation results-predicated that it is possible to design different phase structures for block copolymers by adjusting boundary shape and boundary-block copolymer interactions.