AIM:To investigate the visual acuity situation of preschool children in Miyun county,and to provide information for the prevention and treatment of vision of preschool children.METHODS:Aged 4-6 years old preschool children in three areas of Miyun county attended the vision acuity examination.The result of visual acuity was analyzed.RESULTS:The subnormal rate of visual acuity in 4,5 and 6 years old was 36.29%,24.43% and 20.86% respectively;in urban was 36.76%,and 24.35% for urban-rural fringe,and 17.08% for rural;Mild occupied 84.38% of the total subnormal in visual acuity subjects,and 8.99% for moderate,and 6.63% for serious.CONCLUSION:The age of 4 years old is the highest among vision subnormal for preschool children.The rate of vision subnormal in urban is highest and the mild is the most.Preschool children’s eye care is an important part of children’s health care,the result from the correct analysis is necessary.