The invention discloses an automobile backrest seat cushion with low-temperature radiation electrothermal films to heat. The automobile backrest seat cushion is composed of a backrest, a seat cushion, a waist rest and a head pillow and is characterized in that the plate backrest and the seat cushion are integrated by soft materials and can be placed on a bed to be used at any inclined angle or folded to be stored; the low-temperature radiation electrothermal films are placed in inner interlayers of the backrest and the seat cushion and can efficiently radiate far infrared waves with wavelengths which are close to human body radiation peak wavelength once the low-temperature radiation electrothermal films are powered on; and in order to relieve abnormal stressing of third and fourth lumbar intervertebral discs, the upper portion of cervical vertebra and the lower portion of the back side of a head when a user leans against the backrest seat cushion, the waist rest and the head pillow which are flexible and adjustable in height are arranged on the backrest. When the automobile backrest seat cushion is used, the automobile backrest seat cushion is placed on an automobile seat, the waist rest and the head pillow are fixed according to actual figure height, and then the automobile backrest seat cushion is powered on so that the user can comfortably lean against the backrest seat cushion during automobile traveling; a human body is heated by far infrared resonance absorption so that the waist, the back, the buttocks, legs and feet can be extremely warm, and physical therapy effects are achieved; and the automobile backrest seat cushion is scientific and reasonable in design, practical, convenient, capable of being conveniently used on automobiles and suitable for being used in hospitals, families and various personnel and has inestimable market prospects.