The present invention relates to a graft copolymer including a polysaccharide as a main chain and a phosphorylcholine analogous group-containing monomer as a side chain, and a composition for skin and hair care including the copolymer as an active ingredient. The graft copolymer according to the present invention exhibits more improved moisturizing capacity and better biocompatibility than the existing polysaccharide-based graft copolymer by introducing a phosphorylcholine analogous group-containing compound, and accordingly, the composition for hair and skin care including the same also has improved moisturizing capacity, protection capacity of damaged hair, skin affinity, a skin barrier function, and the like.