Objective To analyze the correlation between the International Caries Detection andAssessmentSystem Ⅱ (ICDAS Ⅱ) and plaque staining in the detection of early caries of deciduous teeth. Methods A total of 100 children with congenital heart disease admitted to our hospital from January to December 2023 were selected as the research objects. All children underwent ICDAS Ⅱ and plaque staining. A total of 16 tooth surface sites were selected, including 54 teeth, 51 teeth, 64 teeth, 74 teeth, 71 teeth and 84 teeth. The caries status was counted in detail and the correlation was calculated. Results The incidence of LI tooth surface demineralization was higher than that of cavity caries, but the difference was not statistically significant (P >0.05). The incidence of other tooth surface demineralization was higher than that of cavity caries, and the difference was statistically significant (P <0.05). The incidence of small plaque on each tooth surface was higher than that of severe plaque, and the difference was statistically significant (P <0.05). Pearson correlation analysis showed that the results of plaque staining were positively correlated with the results of ICDAS Ⅱ, and the difference was statistically significant (P <0.05). Conclusion Both ICDAS Ⅱ and plaque staining can be used for the diagnosis of early caries of deciduous teeth in children with congenital heart disease in Kashgar, and there is a positive correlation between the two.