Objective To conduct an epidemiological survey of common congenital heart disease （CHD） among children in ethnic minority areas in southeastern Guizhou and to explore the influencing factors of delayed medical treatment. Methods From January 2019 to July 2022， 18 850 children aged 3 months to 14 years in Qiandongnan Miao and Dong Autonomous Prefecture were selected； 105 children with CHD were included in the training set， and they were divided into delayed group （80 cases） and non-delayed group （25 cases） according to whether or not to delay medical treatment. In addition， children with CHD （35 cases） from July 2022 to December 2022 were included in the validation set. The general data of the subjects in the two groups were compared and analyzed. Multivariate logistic regression was performed and risk scoring model was constructed. Results The prevalence of CHD in 18 850 children was 5.57‰ （105/18 850）， with the highest prevalence in Liping County， and the lowest in Huangping County. The proportion of children with secondary atrial septal defect was the highest， and that of the aortic valve malformation was the lowest. Among the complex cases of CHD， the proportion of children with single type was the highest， and that of children with three or more types were the lowest. Among children with CHD， the rate of delayed medical treatment was 76.19% （80/105）. The median delay in medical treatment was 12 months， with an average of （18.78 ± 4.77） months. Multifactor logistic regression analysis showed that heart murmur （level 2 ~ 3）， less-educated （primary and secondary school） guardian， family per capita income < 2 000 yuan， and frequent drinking of the guardian were independent risk factors for delayed medical treatment （P < 0.05）， and commercial settlement of medical expenses was independent protective factor （P < 0.05）. Risk scoring model divided the children into three groups： low risk （≤ 80 points）， medium risk （> 80 points and ≤ 134 points） and high （> 134 points） risk group. The evaluation of the model show that it was accurate， effective， safe， and reliable. Conclusion The highest prevalence is observed in Liping County. The proportion of children with secondary atrial septal defect and the proportion of children with single type are the highest. Delayed medical treatment is found in most of the children with CHD. Cardiac murmur， education background of the guardian， per capita family income， guardian alcohol consumption， and medical expense settlement method are all independent influencing factors for delayed medical treatment.