Abstract: Objective: To analyze the relationship between chronological age and the D/L aspartic acid ratio in dentin of the first premolar of Chaoshan population. Methods: Sixty first premolar teeth from living individuals of known age were retrieved. Dentin was extracted from these teeth. The D- and L-aspartic acids in dentins were separated and detected by high performance liquid chromatography (HPLC) system. Linear regression was performed between the D/L aspartic acid ratio of dentins and chronological age. Dentin from another 3 cases was employed to test the accuracy of the regression equation. Results: Linear regression analysis showed a significant correlation between the first premolar dentin D/L aspartic acid ratio and chronological age (P<0.001), the correlation coefficient (r) was 0.967, SE=2.60 years; the racemization ratio k=6.0 ×10^-4/ year. The errors of 3 cases were -0.3 years, +1.6 years and -2.2 years. Conclusion: Aspartic acid racemization in the first premolar dentin can be used as an accurate method to estimate chronological age in the Chaoshan population.