Objective To investigate the biomechanical behavior of patellar cartilage in human knee. Methods Eight human fresh patellar cartilage were used. One-dimensional tensile test and stress relaxation test were performed. Results The destructive load?stretchy ratio?Lagrange spreading stress?Lagrange spreading strain, creep were obtained. The data of stress and strain was fitting with polynomial by the least square method. In addition, the equations of stress relaxation and creep were also obtained. Based on Feng YZ's the semi-linear theory G(t) formula, the constitutive equation K(λ,t)=G(t)T (e) (λ) was obtained. Conclusion The destructive load in one-directional tensile test is 38.54±4.18N, the stretchy ratio is 1.312±0.018, the spreading stress is 6.65±0.83MPa and the strain is 34.0±3.6%; Stress relaxation occurs during the first 7200 second and both of stress relaxation curve and creep curve are the logarithmic relation relative to time.