Abstract: The data in this paper was gathered from 880 cases in Liaoning Province in China, 544 of which are from cities, mainly from Shenyang, and the rest from rural area, mainly from Panshan county. The age of these cases range from 13 to 60 years old. The normal teeth have 23672, dental carries 204 and other teeth 764. Based on the new graduation standard for teeth attrition, the auther aut- hor selected one of the upper and lower jaw teeth. After the numerical values for all the degrees were determined, they were grouped 14 items and 84 to 98 categories. 10 equations on the estimation of age have been established by app- lying the Theory of Quantification Type I and the multiple stepwise regression to the newly established mathematic model, and by the aid of computer science as well. In order to obtain the convenience of usage, these equations have also been turned into 10 tables in estimation of age. The correlation coefficients are 0.92 to 0.97. The errors and reliability of the equations are different from one another as the influential factors (sex, place) are confined to different extent. In order to confirm the reliability of the equations, the equations were examined by 25 skulls. The rate of coincidence of the tested samples with the real age foll- ows as: 72% in±3 years error, 88% in±5 years error and 96% ±7 years error.