Nanocapsule derived from hyperbranched polymer bears a number of active functional groups in the core; such a structure feature renders it possible to meticulously engineer the core of the nanocapsule and thus provides a unique opportunity to evaluate the structure-property relationship. Here the amino protons of HPEI (M-n = 10 000 Da) are 15%, 30%, 60%, and 86% alkylated with 2-dodecyloxymethyloxirane, leading to core-shell structured amphiphilic macromolecules (CAMS) with such different shell density as HP(EI-OH(0.15)C12(0.15)) (3a), HP(EI-OH(0.30)C12(0.30)) (3b), HP(EI-OH(0.60)C12(0.60)) (3c), and HP(EI-OH(0.86)C12(0.86)) (3d), respectively. The cores of 3a-3d are further chemically modified by complete alkylation of the residual amino protons with propylene oxide, leading to HP(EI-OH(1)C12(0.15)) (4a), HP(EI-OH(1)C12(0.30)) (4b), HP(EI-OH(1)C12(0.60)) (4c), and HP(EI-OH(1)C12(0.86)) (4d), respectively. Nanocapsule with thick shell is also obtained by alkylation of HPEI with epoxy polystyrene (M = 1800), leading to HPEI with 15% (HP(EI-OH0.15PS0.15), 7a), 30% (HP(EI-OH0.30PS0.30), 7b), and 60%-(HP(EI-OH0.60PS0.60), 7c) of the amino protons being alkylated. Water-soluble, anionic dyes can be encapsulated by these CAMS. It is found that 7a-7c exist as unimolecular inverted micelles in the tested range while 3a-3d and 4a-4d exist as aggregates in chloroform, indicating that a thick shell is crucial to the nature of unimolecular micelle. It is also found that the guest releasing ability is dependent on the nature of the functional groups in the core but independent of the shell density: thus, encapsulation of methyl orange by 3a-3c is reversible, while that by 4a-4c is irreversible. Congo red can be encapsulated by the aggregate of 3a-3d or 4a-4d, but excessive Congo reds cause precipitation of the aggregate. Finally, it is noticed that the molecule recognition property is also dependent on the nature of the functional groups in the core but independent of the shell density and shell thickness; as a result, a CAM with a designed core can highly selectively encapsulate a guest from a mixture.