Aquaporin-Z (AqpZ) are water channel proteins with excellent water permeability and solute rejection properties. AqpZ can be reconstituted into vesicles utilizing cell-like bilayer membranes assembled from amphiphilic block copolymers, for the preparation of high-performance biomimetic membranes. However, only a few copolymers have been found suitable to act as the membrane matrix for protein reconstitution. Hence, this work analyzes the mechanism of protein reconstitution based on a composition-reconstitution relationship. The vesicle formation and AqpZ reconstitution processes in various amphiphilic block copolymers were investigated in terms of size, morphology, stability, polymeric bilayer membrane rigidity, and thermal behavior. Overall, this study contributes to the understanding of the composition-reconstitution relationship of biomimetic membranes based on AqpZ-reconstituted polymeric vesicles.