[Objective] To explore the change of biomechanics about human tendon with"?"irradiated which was universal used by domestic and foreign.[Methods]Twenty-four upper limb tendon of human with the same length were divided into two groups,group A(12):nonirradiated group,group B(12):2.5 Mrad gamma irradiated group.Material properties and structural properties were determined with WDW-3020 electron universal testing machine.[Results]The mean length of the tendon was 99.15% of control,the elongation to failure was 93.46%,the linear stiffness was 95.27%,the energy to maximum force was 93.60%,the maximum stress was 84.88%,the strain to failure was 85.82%,the linear modulus was 90.40%,the strain energy density to maximum was 66.73%.Difference was noted after compared hetween group A and B(P