rehabilitation instrument laser irradiation on joint kneeTherapeutic Principle Low intensity laser applied to biology, there is no irreversible damage to biological organization, just cause a series of physiological and biochemical changes,such as anti inflammatory and analgesic, convergence wound, desensitization, adjust the body function. Our machine using 808nm for medical use and 650nm for household use, through specific parts of irradiation and using light radiation of laser and wavelength relation to