The principle of treating dysmenorrhea with the same frequency light wave dysmenorrhea physiotherapy instrument is to raise the temperature of uterus and activate uterine cells according to the far infrared ray with the same frequency as human body; Far infrared rays can reach the uterus directly, with accurate treatment and quick effect; Dysmenorrhea can be gradually recovered by continuous use. Experts combined far infrared rays with the characteristics of female dysmenorrhea treatment, made a technical breakthrough, applied for a patent and applied this patented technology to products, which solved the unspeakable problem of female dysmenorrhea.