OBJECTIVE: To investigate the prevalence of deciduous dental caries in preschool children aged 36-71 months as well as the eruption and caries status of permanent teeth in children aged 60-71 months in Guangzhou city, providing references for oral health work. DESIGN: This study was a cross-sectional study design. SETTING: The study was conducted in 34 kindergartens in the central and non-central urban areas of Guangzhou city. PARTICIPANTS: 14 883 preschool children aged 36-71 months in Guangzhou city were included in the ultimate analysis. MAIN OUTCOME MEASURES: The prevalence of dental caries and other indicators of deciduous teeth, eruption and caries status of permanent teeth in children aged 60-71 months. RESULTS: The prevalence of dental caries in children aged 36-47 months, 48-59 months and 60-71 months were 41.6% (95% CI: 40.1%, 43.1%), 57.1% (95% CI: 55.8%, 58.5%) and 65.2% (95% CI: 64.0%, 66.4%), respectively. Mean decayed-missing-filled teeth increased with age, with differences between genders and areas. The percentage of permanent first molars and central incisors eruption in children aged 60-71 months differed, and caries conditions varied. CONCLUSION: The problem of early childhood caries in preschool children in Guangzhou city is prominent. Prevention should be strengthened from early life, and oral health education and publicity enhanced to narrow regional oral health gaps.