Objective To investigate the biomechanical behavior of human knee meniscus. Methods Human fresh meniscus was obtained from death fresh bodies caused by fulminant trauma. One-dimensional tensile test and stress relaxation test were performed. Results The destructive load?stretchy ratio?Lagrange spreading stress?Lagrange spreading strain were obtained. The data of stress and strain was fitting with polynomial by the least square method. In addition, the equation of stress relaxation was 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 destructive load in one-directional tensile test is 40±3N, the stretchy ratio is 1.369±0.048, the spreading stress is 7.27±0.59MPa and the strain is 43.8±6.6%; Stress relaxation occurs during the first 1200 second and the stress relaxation curve is the logarithmic relation relative to time.