Narcolepsy is a chronic brain disorder. The mechanism is the impairment of brain controlling of sleep and wakefulness. The cause of this disease is still unclear, but common symptoms include excessive day time sleepiness, cataplexy, hypnogogic hallucination, sleep paralysis, and sleep disturbance. Because these symptoms are easily confused together in many situations, it is difficult for doctors to make the diagnosis. Therefore, medical treatment for patients is always delayed. According to previous research report, narcoleptic patients are often delay diagnosis for 10 to 15 years after the onset of the disease. Clearly, to make the diagnosis of narcolepsy is very difficult. Another cause for the delay is the method for diagnosing narcolepsy, which mainly rely on sleep examination instruments and the testing of hypocretin concentration in the cerebrospinal fluid. However, these tests are difficult to carry out in many areas, and diagnosing narcolepsy is still difficult in many countries. To the patients and their families, developing a fast and accurate method or tool for diagnosing narcolepsy is of the utmost importance.