Due to a large difference in storage modulus below and above the glass transition temperature, a novel shape-memory poly[(methyl methacrylate)-co-(N-vinyl-2-pyrrolidone)]/poly(ethylene glycol) semi-interpenetrating polymer networks structure was synthesized, which is stabilized by hydrogen-bonding interactions. The recovery ratio of these polymers could reach 99%. In such a system the maximum molecular weight of PEG required for the semi-IPNs formation reaches 1000.