Degradable hollow nanospheres are prepared by self-assembly of rod-coil Alg-g-PEG/α-CD (Alginate-g-Poly(ethylene glycol)/α-Cyclodextrin) complexes in water, in which the rod-like segments were formed by inclusion between α-CDs and grafted PEG chains and the coil-like segments were protonated alginate backbones.