A hot-melt polyester tape and a preparation method thereof is provided, the hot-melt polyester tape comprises a PET film layer which has a thickness of 10-20 μm, and one side of the PET film layer is coated with a hot-melt glue layer which has a thickness of 2-5 μm; the preparation method thereof comprises sizing, curing, slitting and winding formation. The hot-melt polyester tape of the invention has the PET film layer and the hot-melt glue layer, and such hot-melt polyester tape is added with a layer of hot-melt glue compared to a conventional PET film, which makes it have higher extension capacity and not easy to break, the extension strength is much higher than the national standard, and the hot-melt polyester tape has the functions of waterproofing and reinforcement.