Objective To investigate the status of dental caries on deciduous teeth and influencing factors among preschool children in Xi'an,provide a scientific basis for making prevention and intervention measures of dental caries in children. Methods The cluster random sampling method was used in this study.A total of 881 preschool children in 3 kindergartens were surveyed,the questionnaires were completed by their parents.The results were analyzed by SPSS 18.0. Results The prevalence,mean dmft and filling rate of dental caries among preschool children in Xi'an was 51.08%,2.25 and 8.88% respectively.There were significant differences (P<0.05) in caries prevalence and mean dmft among different age groups,the caries prevalence and mean dmft increased as children were growing up.There were no significant differences in caries prevalence and mean dmft among different gender groups.The results of Logistic regression analysis showed that the risk factors of caries in preschool children were the older age,the later weaning time,the higher frequency for daily consumption of sweets,and the higher debris index.The results also showed that the correct brushing method,brushing frequency and using fluoride toothpaste were protective factors for children suffering from caries. Conclusions The prevalence of dental caries in preschool children is relatively high in Xi'an,however,the filling rate is low.To strengthen the publicity of oral health knowledge,culture scientific oral hygiene habits,take topical fluoridation,pit and fissure sealant are very important for preventing dental caries of children.