Provided is a resin composition for paper-coating comprising aliphatic polycarbonate having an average molecular weight of 30,000 to 300,000 obtained by reaction of one or at least two different kinds of epoxide compounds selected from a group consisting of (C2-C10)alkylene oxide substituted or unsubstituted with carbon dioxide, halogen, or alkoxy; (C4-C20)cycloalkylene oxide substituted or unsubstituted with halogen or alkoxy; and (C8-C20)styrene oxide substituted or unsubstituted with halogen, alkoxy, alkyl or aryl, wherein it contains 0 to 40 weight % of polyolefin-based resin such as polyethylene or polypropylene, based on the total amount of the composition. In addition, the present invention relates to a paper coating method of extrusion-coating the resin composition for paper-coating on paper at 130 to 250° C. to manufacture a coated paper.