Abstract: Objective To know the main influences on sleep disorder among urban Chinese children aged 2 to 5 years.Methods 7 282 children aged 2 to 5 years were selected by stratified sampling from twelve software.Results The total icidence of sleep disorder at 2 to 5 years old was 19.75%,and gender difference existed for its distribution.There were relative high rates in omnambulate and night terror for gilrls while molar and breathing with mouth for boys.Sleep disorders for children were ascrided to collective effects from multifold influences such as heredity,diseases,perinatal factors,children character,sleep-associated habits,family enviornment,parents' breeding mode and so on.Conclusion Enhancing sleep health education and carying out community screening of sleep problems to construct a good enviornment is effective in preventing sleep disorders.