Objectives To know about the psychological and behavioral development of children aged 0 to 3 years in Shunyi District of Beijing over the past three years, and to evaluate the application effects of early warning signs. Methods From September, 2018 to September, 2021, a total of 1 360 children who received assessment by Gesell Developmental Scale(GDS) in Maternal and Child Health Care Hospital of Beijing Shunyi District were selected, and the results of early warning signs of these children in community physical examination were retrieved. Then the results of two assessment methods were statistically analyzed. Results Among 1 360 children assessed by GDS,the proportion of boys(69.9%) was significantly higher than that of girls(30.1%) (χ² =214.412,P<0.05). The development quotients (DQ) of language and personal-social ability area of boys were significantly lower than those of girls (t＝4.201,2.186, P<0.05). In terms of early warning signs, children under 12 months old were mainly backward in the development of gross and fine movements, while children aged 12 to 36 months were mainly backward in language development.There was statistical difference in the composition ratio of early warning positive items among children in different age groups (χ²=36.750, 5.762, 9.966, 8.895, 57.731, 231.749, 105.385, 56.919, P<0.05). The result of early warning signs was moderately consistent with that of GDS (Kappa=0.559, P<0.05).The DQ value of adaptability in children with two or more positive early warning signs was significantly lower than that of children with one positive warning sign (t=5.718,P<0.05). Conclusion More attention should be paid to the development of boys' psychological and behavioral development, as well as the promotion of early childhood development, especially for the gross and fine movements development of infants, and the language development of young children.