In the present study, the phase behaviors of the bulk columnar phase AB diblock copolymers under spherical and prolate confinements are studied by the self-consistent field theory. By changing the size of the confined spaces, the developing law of phase morphology, free energy, conformational entropy and interaction energy of AB diblock copolymers are systematically summarized and compared. The results show that，in the confined spaces, diblock copolymers possess various phases. In the spherical confinement, the phase structures of diblock copolymers exhibit better symmetrical characteristics due to the identical frustration suffered from different dimensions. However, because the different frustrations and orientations of polymer chain in different dimension directions are introduced by prolate confinements, the phase structural symmetry of diblock copolymers was significantly broken.