Nightmares are sleep disorders in which dreams with horrific content and causing anxiety and fear are the main manifestations. Nightmares are common in children and can occur at any age, most often in preschool and school-age children. The appearance of nightmares is mainly related to mental stress, emotional disorders and adverse stimuli, but some nightmares are also a specific reaction to physical illness. Psychological factors: The most typical nightmare is the traumatic dream, which means that the dreamer had a more sinister experience or serious trauma in the past, and these experiences and traumas often reappear in the dream. Environmental factors: excessive tension and excitement before bedtime, for example, children leaving their parents for the first time to sleep in an unfamiliar environment, various internal conflicts and anxiety can trigger this disorder, listening to horror stories and watching horror movies before bedtime is also one of the triggers. Physical illness: when the body is sick, such as headache and fever, bad heart caused by lack of oxygen or blood supply to the brain, or an organ lesion caused by the not, may be manifested in the form of nightmares. Drug factors: Drugs such as antidepressants, barbiturate sedatives and narcotics have side effects that may cause nightmares. Drugs can indirectly change the balance of certain chemicals in the brain, which in turn can induce nightmares. Sleep disorders: Nightmares accompanied by rough movements such as punching, kicking, rolling and screaming are a common manifestation of sleep behavior disorders, often occurring in Parkinson’s disease or other neurodegenerative disorders. Dreaming is a part of normal sleep, nightmares appear more because of the accumulation of mental and emotional stimulation, appropriate relaxation should be able to get relief, frequent nightmares should be looking for possible causes, it is recommended that the hospital to carry out relevant examinations to clarify the cause.