Generally cause 3-year-old children have difficulty falling asleep, mainly include the following aspects: first, due to the environment is not very suitable to cause, fall asleep when the surrounding environment is very noisy or bright light, will cause children to fall asleep is very difficult, need to let the light dimming and keep the room quiet, is conducive to children fall asleep. Secondly, due to children suffering from diseases caused by the difficulty in falling asleep, if suffering from abdominal pain or headache, cough and other diseases, it is often difficult to fall asleep, should be timely treatment of the corresponding primary disease, the primary disease control after the difficulty in falling asleep will naturally subside.