A chip on film package structure including a flexible film, a patterned metal layer, a chip, a patterned solder resist layer, and a code-included pattern is provided. The flexible film comprises a chip mounting region and a peripheral region surrounding the chip mounting region. The patterned metal layer disposed on the flexible film. The chip mounted on the chip mounting region and electrically connected to the patterned metal layer. The patterned solder resist layer exposing the chip mounting region and covering a part of the patterned metal layer. The code-included pattern disposed on the peripheral region of the flexible film. The code-included pattern comprises a plurality of machine-readable data. A method for reading a code-included pattern on a package structure is also provided.