The aim of this investigation was to analyse the dental caries prevalence, patterns and trends of all age groups in Liaoning province.The representative samples were selected by multi-stage, stratified and random sampling, which included subjects aged 5,12,35-44 and 65-74 years. Clinical examination was based on WHO methodology(4th Ed). Student's t test and Chi-square test were applied for statistical evaluation of the mean caries experience(DMFT/dmft) and the prevalence proportion rates of dental caries (PP) between 1995 and 2005 using SPSS 12.0 software package.At age 5,12,35-44, the PP was 73.86%,30.05% and 63.89% respectively,which was lower than in 1995, the number being 89.49%, 59.19% and 70.26%. However, at 65-74 years, the PP was 67.40% in 2005, and there was no significant difference compared with 1995. For the two national survey, the PP and DMFT were higher in urban than in rural area. But the dmft in 5-year-old in urban was lower than in rural in 2005.The trend of dental caries in children and adults was declined in 2005, but it was still higher. It is essential to strengthen oral health education and promotion and continuously implement preventive oral care technique in Liaoning province.