Objective:The aim of this study was to determine the stress-strain properties of Beagle Dog’s periodontal ligament(PDL)and compare response characteristics of PDL in different root anatomic level and different loading rate status in uniaxial tensile stage for further exploration of the elasticity modulus of PDL. Methods:4 Beagle Dogs were killed before the bone-PDL-tooth complex was cut and the transverse samples were made. The experimental samples were divided into 3 groups according to the anatomic level of the root(cervical margin,mid-root,and apical),and each group contained 8 samples. Samples were randomly selected by rate of v1=0.05 mm/s and the other four samples by v2=0.01 mm/s. The uniaxial tensile test was performed and stress-strain curves of PDL was obtained. The elastic modulus was obtained by calculating the slope of the straight line in each segment,and paired t test analysis of influence of tensile rate on the elastic modulus of the PDL was carried out. The randomized block design and variance analysis was set to evaluate the difference caused by different anatomic level of the tooth root. Results:All samples of the stress-strain diagram showed a bilinear property. In different rates,the elastic modulus of linear region differed significantly in mid-root(P=0.016 < 0.05)and apex(P=0.016 < 0.05)but cervical margin represented no significant difference(P > 0.05). and the elastic modulus of toe region differ significantly in mid-root(P=0.001 < 0.05)and cervical margin(P=0.002 < 0.05)but no significant difference in apex(P > 0.05). The difference of elastic modulus was not significant between the different anatomical level of the root (P > 0.05)but the difference between the size of toe region was significant(P < 0.05). Conclusion:The tensile stress strain curves of Beagle Dog’s PDL can be fitted to the bilinear property. The elasticity modulus varies from 0.021 ± 0.003 MPa to 1.150 ± 0.235 MPa. The tensile rate can significantly affect the elastic modulus of the PDL. Difference caused by anatomic levels of PDL was not significant.to elasticity modulus but significant to the size of toe region.