In this paper a split Hopkinson tension bar system is improved by adding wave absorbers into the incident bar and the transmission bar, and the reflected waves in the input and output bar in dynamic tension experiments will be eliminated. The dynamic tension recovery technique is developed by adopting the improved bar system. Dynamic tension and recovery experiments are conducted to obtain the adiabatic and isothermal stress-strain responses of the TC11 alloy at high strain rates. And the adiabatic softening effect is experimentally uncoupled from the strain-rate strengthening and strain hardening effects. The quasi-static tensile tests under different initial temperatures are also carried out to study the thermal softening effect which is described by using Johnson-Cook model. The model is modified by introducing the value of adiabatic temperature rise in dynamic tensile process.When the adiabatic curves of modified model and experiment are in good agreement, the conversion factors of plastic dissipation power to heat at different strain rates will be determined. And the conversion factor of the strain rate 500s-1 is found to be less than that of the strain rate 190s-1.