Objective：To investigate the viscoelastic mechanical behavior of human periodontal ligament（PDL），obtain relevant data through creep test，construct a three-parameter viscoelastic constitutive model and obtain model parameters. Methods：Four human bone-PDL-tooth complex was cut to make the transverse samples. A dynamic thermomechanical analyzer was used to perform creep tests，and time-dependent test data were obtained. The three-parameter Zener model was constructed based on continuous medium mechanics，and the experimental data were fitted to obtain the specific characteristic parameters of the model. Results：The curves of the four samples were consistent，the correction coefficients are all above 0.95，the highest fitting sample is 0.986 54，and the residual sum of squares are all small. Conclusion：It is proved that the Zener model can be used to describe the creep characteristics in the viscoelastic mechanical behavior of human PDL.