A blended polyester laminating film resistant to discoloration caused by cooking, comprising polyethylene terephthalate and polybutylene terephthalate. The blended polyester laminating film comprises three layers, i.e., upper, middle, and lower layers. One surface layer contains SiO2 in a mass fraction of 1200-2000 ppm added by in-situ polymerization. The blended polyester laminating film is manufactured by a three-layer coextrusion biaxial stretching method, and the manufacturing method is 240-275° C. A film-laminated metal sheet manufactured from the blended polyester laminating film has excellent resistance to discoloration caused by cooking, and is applied to metal containers for food and beverage packaging that require high-temperature sterilization.