Limb lengthening by applying the tension-stress stimulated epiphyseal cartilage as a method ofclinical application has been gained popularity recently. Isolated fresh femur bones from 20immature New Zealand white. rabbits were tested under INSTRON machine to investigate theplastic elongation, breaking force and stress relaxation of the biomechanics properties of theepiphyseal cartilage. The result showed that the mean plastic elongation of isolated femur was greatin connection with the tension force increased or persistence time prolonged. The tension relaxationwas decreased in logarithmic curve by time prolonged. Our findings suggest that the low tensilestress had stimulating effects on the epiphyseal cartilage increased in length and no influenced theultimate strength of bone. The Persistence time which tension force performed prolonged, the effectof limb lengthening could be enhanced. It is suitable for the tension force level which higher thanthe original force against stress relaxation. The purpose of this study was to provide theoreticalbasis for clinic bone lengthening.