The invention discloses a plastic film cutting device. The plastic film cutting device comprises a cutting table for bearing the plastic film, an electric heating bar arranged on the cutting table, a heat transfer part connected to the bottom end of the electric heating bar, and a positioning assembly positioned at the lower end of the heat transfer part and used for flattening the plastic film. The invention provides a cutting device suitable for a plastic film, the plastic film is cut in a hot ironing manner, the film is not torn by cutting pressure, and efficiency and high quality are achieved; positioning assemblies are arranged at two sides of the heat transfer part for fixing the plastic film and preventing cutting malposition caused by moving of the plastic film.