The present invention relates to a blend of polyolefin comprising a modified chlorinated polypropylene. This invention provides a blend of polyolefin comprising a novel amine modified chlorinated polypropylene capable of improving printability by promoting adhesion with ink when the ink is printed or coated on plastic products including film and sheet. The present invention provides a novel blend of polyolefin comprising a modified chlorinated polypropylene, which is prepared by substituting 1-99.9 mole % of chlorine of a chlorinated polypropylene, whose chlorine content is 1-75 wt % and whose number average molecular weight is 100-400,000, with ammonia or an amine compound and is capable of improving dyeability and adhesion performance. This invention also provides the modified chlorinated polypropylene and a method for preparing the same.