Objective: To analyse factors associated with the susceptibility of early childhood caries (ECC), populations with a high risk of ECC were screened and guidance for ECC prevention was proposed. Methods: A total of 392 children aged 24 to 71 months were selected for oral examination in Qingdao. Parents or guardians of the participants completed the questionnaires and decayed missing filled surface (dmfs) were recorded. Differences in caries condition and oral health behaviour in different families were compared. Risk factors related to ECC were screened. The subjects were finally grouped based on the obtained dmfs into three groups: caries-free, ECC and S-ECC (severe ECC). Association of risk factors with the caries status was analysed using the Kruskal-Wallis test, the chi-square test and logistic regression analysis. Results: There were significant differences among the caries-free, ECC and S-ECC groups in three parameters: eating too many sweets each day, brushing before and after sleeping, and whether parents helped to brush (P 0.01). Combined factors such as the parents' level of education, oral health knowledge, attitudes, the family's annual income, the age of children when they start to brush and not brushing regularly were also significantly related to ECC (P 0.05). No significant differences were observed among the three groups for these factors, including birth condition and nursing state, physical condition of the mother during pregnancy, feeding situation, if a pacifier was used during sleep, duration of brushing, frequency of mouth rinsing after meals each day and brushing with fluoride toothpaste (P > 0.05). Conclusion: Eating a lot of sweets, an incorrect brushing method, starting brushing at a later stage and not brushing regularly are susceptible factors for ECC. Emphasising oral health knowledge to parents and guardians, conducting proper brushing methods, limiting the frequency of sweets being eaten and avoiding an inappropriate habit of eating sweets are very important factors in the prevention of ECC. Keywords: children, decayed missing filled surface (dmfs), early childhood caries (ECC), prevalence, susceptibility