Abstract： Objective　To study the biomechanical properties of human mandible under tension load and deduce the constitutive equation. Methods　100 speciments taken from five mandible of fresh human cadavers were examined on INSTRON by a group of tensile tests at different strain rates (0.000 3/s、0.003 0/s、0.030 0/s、0.300 0/s). Bone mineral density of every individual mandible was measured. The effect of strain rate (), bone mineral density (ρ) on youngmodulus (E), strength (σu) and ultimate strain (εu) was studied and the constitutive equation was deduced using the following model: Y=aρbεc. Results　(1)σu=126.36ρ1.880.044（P<0.01）,(2)E=25 170.97ρ0.440.052 （P<0.01）， (3)εu=0.008 8ρ1.89-0.028 （P<0.01）, (4)σu=6 309. 57ρ0.96ε0.0560.80（P<0.01）. Conclusions　Strain rate and bone mineral density are important factors for the biomechanical properties of human mandible under tension load. The results above may modelize and characterize the constitutive relation within small strain rates. From the constitutive equation, we could estimate the stress level of the mandible and assess the possibility and degree of mandible injury.