The present invention provides a surface-coated cathode active material and a method for preparing the same, the surface-coated active material comprising: a cathode active material; and a nanofilm coated on a surface of the cathode active material, wherein the nanofilm includes polyimide (PI) and a fibrous carbon material. According to one embodiment of the present invention, when a surface of a cathode active material is coated with a nanofilm including polyamide and a fibrous carbon material, a direct contact with an electrolyte of the cathode active material is prevented so as to suppress a side reaction between the cathode active material and the electrolyte, such that the of a secondary battery is capable of being remarkably improved. Particularly, it is possible to improve life and conductivity under high-temperature and high-voltage conditions.