AIM:To investigate the risk factors in early childhood caries. METHODS:1 860 children aged 8-36 months in Shenyang were surveyed and chose 120 children with early childhood caries and 120 caries-free children. Data were collected by questionnaire from their mother and oral examination. RESULTS: The degree of branching?DMFT and capability of dental plaque production acid of mother were strongly related to early childhood caries ( P 0.01) ; the pattern of infant feeding was not related to early childhood caries( P 0.05); length of breast-feeding?nighttime bottle and sweet habit were related to early childhood caries( P 0.05);oral health was strongly related to early childhood caries( P 0.001).CONCLUSION:Mother plays a very important role in development of early childhood caries; to protect early childhood caries, we must choose correct habit of breast-feeding and control oral health.