Provided are a polymer resin composition and a method of preparing the same. The polymer resin composition includes: a polymer resin; 0.01-10.0 parts by weight of flaky pigment particles having an inverse aspect ratio of 0.01-0.1 based on 100 parts by weight of the polymer resin; and 0.01-10.0 parts by weight of polyhedral pigment particles having an inverse aspect ratio of 0.300-0.999 based on 100 parts by weight of the polymer resin. Using the polymer resin composition, a polymer resin molded product having excellent appearance, i.e., having a uniform color even in resin flow lines or resin weld lines, and in which there is no degradation in the physical properties of the polymer resin contained therein can be manufactured at a low cost.