Abstract: Objective The investigate the correlation between deciduous caries of preschool children and knowledge of oral health of their parents in Jinan, so as to provide basis for targeted oral health care service on children. Method The representative samples were selected by multi-stage, stratified and random sampling from 4 regions in Jinan City (2 rural areas and 2 urban areas). Dental caries of 538 children were recorded (urban: 268; rural: 244) according to Oral Health Surveys: Basic Methods from World Health Organization. The questionnaires on oral health behaviors were finished by the parents of the 538 children. chi-squre test. Results 1. The prevalence and dmft of deciduous caries of preschool children in Jinan City were 71.95% and 3.84 respectivel．The prevalence of deciduous caries in preschool children was 62.18％in urban areas and 81.72％in rural areas. The difference was statistically significant. 2. The frequency of eating sugary foods of preschool children was high. The frequency of taking in sweets, sodas and carbonated beverage was higher in rural children than in urban children. Urban children began to brush teeth earlier than rural children; their frequency of brushing teeth and proportion of using fluoridated toothpaste were also higher compared with rural children. 3. The parents of preschool children showed relatively poor in knowledge of oral health (59.48%), and parents in urban areas (66.07%) were better than those in rural areas (52.88%). There was significant difference in comparison between rural and urban areas. Conclusion Decidous caries status of preschool children was positively correlated with oral health knowledge of parents; publicity and education on oral health knowledge of parents, especially parents in rural areas, should be strengthened in Jinan City.