Objective: To explore the clinical characteristics of functional constipation in children aged 0-4 years in Xiamen area and analyze the risk factors for its occurrence. Methods: A total of 1558 children aged 0-4 years old from 4 community health service centers, three kindergartens and children"s hospitals in Xiamen from March 2023 to March 2025 were selected to analyze the incidence of functional constipation. 240 children diagnosed with functional constipation will be selected as the case group, and their main symptoms and onset time will be analyzed. Another 240 healthy children were selected as the control group, and the general characteristics of the two groups were compared. Logistic regression was used to analyze the risk factors for functional constipation in children aged 0-4 years old. Results: 240 children were diagnosed with functional constipation, with an overall prevalence rate of 15.40%. According to statistical analysis, there is a statistically significant difference in the incidence of functional constipation among different age groups (P<0.05), showing a trend of gradually increasing incidence with age. 82.50% of cases had prolonged intervals between bowel movements; Difficulty in defecation 76.67%; 71.25% had abnormal stool characteristics; 24.17% have symptoms of anal pain or anal fissure; 18.75% showed symptoms of loss of appetite; 15.42% had symptoms of abdominal distension; There were no significant differences between the case group and the control group in terms of gender, age, height, weight, and allergy history (P>0.05). However, there were significant differences between the case group and the control group in terms of family history of constipation, daily water intake, feeding methods, outdoor activity time, dietary fiber intake, defecation training, time to add complementary foods, overly refined diet, imbalanced diet, picky eating frequency, and loss of appetite (P<0.05); Multivariate logistic regression analysis found that family history of constipation did not show statistical significance in this study (P=0.078). The main independent risk factors include: insufficient water intake (OR=2.061), artificial feeding (OR=1.906), insufficient outdoor activity time (OR=1.802), insufficient dietary fiber intake (OR=2.781), lack of bowel training (OR=2.129), improper timing of complementary foods (OR=1.970), overly refined diet (OR=2.253), and frequent picky eating (OR=2.573). These factors significantly increase the risk of functional constipation in children (P<0.05). Conclusion: The incidence of functional constipation in children aged 0~4 years in Xiamen is 15.40%, which increases with age. Children with functional constipation mainly have prolonged defecation intervals, difficulty in defecation, and abnormal stool characteristics. Insufficient water intake, artificial feeding, insufficient outdoor activity time, insufficient dietary fiber intake, lack of bowel training, improper timing of complementary food addition, overly refined diet, and frequent picky eating are all risk factors for functional constipation in children of this age group.