A gelatinize hairdressing foil and its preparation method are disclosed. One surface of said gelatinize hairdressing foil is a dark side, which contacts with hair, and an other surface of said gelatinize hairdressing foil is a bright side. Said dark side is provided with a zonal gelatinize layer. An anti-adhesive layer can be provided on said bright side. The hairdressing foil can contain an aluminum foil, can be provided with a release layer on said dark side, and can be provided with aluminum foils on both surfaces and a plastic film between said two aluminum foils. When quiff is put on said dark side, it is adhered by the release layer on the dark side. Therefore, the quiff is apt to form a layer instead of a tangle, and when liquid medicine for perming and dyeing is coated on hair, each hair could be coated with said liquid medicine.

A method for successively performing hair dyeing and hair straightening, the method including the steps of: performing dyeing on hair; applying, to the hair immediately after being subjected to dyeing, a reducing first agent containing a basic dye and/or an HC dye, and leaving the hair for a certain time, thereby performing reduction on cystine bonds; shaping the hair that has been subjected to reduction into a straight configuration; and applying an oxidizing second agent to the hair that has been shaped into a straight configuration, and leaving the hair for a certain time, thereby performing oxidation for reforming the cystine bonds.