【Objective】 To understand sleep time and the prevalence of sleep disorders about migrant preschool children in Changning district, and to explore the influencing factors of sleep disorders. 【Methods】 550 migrant preschool children were selected with multi-phase sampling. Their parents or fosters were interviewed with general and sleep health questionnaire. 【Results】 The mean sleep time was (11.19±1.22) hours usually and only (10.87±1.37) hours on weekend about migrant preschool children. The sleep time of 3~4 years old children was shorter than foreign children,and the sleep time of 5 years old children on weekend was less than the standard. The difference of sleep time between boys and girls was not significant. The sleep time was different among different age groups. The prevalence of sleep disorders was 50.30%, in which the prevalence of boys was 50.88%, and the girls was 49.53%, the difference between them was not statistically significant (χ²= 0.089,P>0.05). The factors affecting sleep time and the prevalence of children were violent activities in the bedtime, sleeping habits of parents and other factors. 【Conclusions】 Sleep time of migrant preschool children in Changning district is relatively less and the prevalence of sleep disorders is higher compared to the existing data, which should be paid to a good attention.