The surface functionalities of nanomaterials provide an invaluable resource to biomaterials science in the form of biomolecular recognition, sensing, self-assembly and drug delivery. This paper presents a one-step procedure for the facile preparation of highly cross-linked raspberry-like nano/microspheres by the dispersion polymerization of polyethylene glycol dimethacrylate and N-vinylimidazole. Ionic liquid-functionalized reactions were then conducted on the surface of the raspberry-like nano/microspheres to investigate the effects of the functional groups on the peptide adsorption in aqueous media. Various characterization methods were employed to characterize the as-prepared nano/microspheres and to track the experiment process. The results reveal that the nano/microspheres were raspberry-like, monodisperse and stable. It was also found that the adsorption of immunostimulating hexapeptide from human (IHH) was correlated with the surface properties of the ionic liquid-functionalized nano/microspheres, which demonstrated their potential use for the immobilization and release of IHH in practical application.