Macromolecule flame-retardant polyester as well as preparation method and application thereof

The invention relates to macromolecule flame-retardant polyester as well as a preparation method and application thereof. The macromolecule flame-retardant polyester is mainly synthesized from terephthalic acid, glycol and a flame-retardant functional monomer via copolycondensation, and the molecular weight of the polyester is 1000-80000 g/mol, wherein the flame-retardant functional monomer is a flame-retardant monomer with at least two hydroxyl groups, two carboxyl groups, two ester groups, or one hydroxyl group and one carboxyl group. The macromolecule flame-retardant polyester prepared from the flame-retardant functional monomer with the terephthalic acid and the glycol via copolycondensation can be used as a polyester flame-retardant material independently, can be also used as a flame-retardant additive which is blended with a PET material, or is subjected to multi-layer coextrusion with PET, and the flame retardancy of the PET is greatly improved. The problem that PET plastic, films or plates of a conven