A facile yet universal approach to the self-assembly of uniform polymeric nanovesicles into bilayer supervesicles is developed using a water-in-1-butanol emulsion soft-confined system. The enclosed bilayer is constructed by polymeric nanovesicles, forming hierarchical supervesicles. Interestingly, the bilayer structure of supervesicles from symmetry to asymmetry is well tailored by simply mixing two different sizes of uniform nanovesicles. The larger nanovesicles are more likely to be segregated in the outer layer, while the smaller nanovesicles tend to be segregated into the inner layer, forming asymmetric hierarchical supervesicles. Different cargoes can thereby be well selectively encapsulated into the inner-layer and outer-layer multicompartment of the asymmetric supervesicles by loading different cargoes into the cavities of the original vesicles with different sizes separately. Such selectable multicompartmental encapsulation provides the possibility to realize the multiple functions of polymeric vesicles and has not been reported to date.