Occasional insomnia is not harmful to the body, but if long-term severe insomnia is harmful to human health, mainly manifested in memory loss, immunity decline, physical function decline and mental illness risk rise. 1. Memory loss: long-term insomnia makes the brain unable to fully rest, poor concentration, logical thinking ability to decline, thus making the efficiency of work and study. 2. Weakened immunity: long-term sleep deprivation can cause increased sympathetic excitability, the body’s metabolic rate increases, the immune system is weakened, increasing the likelihood of various bacterial and pathogenic infections, or aggravate the original symptoms. 3. Decline in physical function: frequent insomnia, sleep disorders can cause abnormal functioning of the body’s organs, easily triggered by hypertension, diabetes, neurasthenia, cardiovascular and cerebrovascular accidents. 4. Increased risk of mental illness: long-term insomnia puts people in a state of mental tension for a long time, which may cause numbness and depression, easy to be impatient and agitated, and great mood swings. Insomnia seriously affects people’s mental state, easily lead to neurasthenia, depression, anxiety and other diseases. If the patient long-term insomnia and the more serious lead to affect the normal life, should go to the hospital in a timely manner, under the guidance of the doctor to identify the causes of active treatment, so as not to delay the condition.