A quasistatic compression experiment at room temperature was performed on the TC18 titanium alloy using an electronic universal testing machine to obtain the experimental data of the alloy under quasistatic conditions. Accordingto the experimental data, the dynamic mechanical properties of TC18 titanium alloy at 298 K, 523 K, 773 K and 1 023 K with strain rates of 500 s-1, 1 000 s-1 and 1 500 s-1 were tested using a split Hopkinson pressure bar. And the stressstrain curves of the alloy under dynamic compression at high temperatures were obtained. Based on the above experimental data, the J-C model was used to fit the dynamic plastic constitutive relation of the alloy under high strain rate. Finally, the dynamic plastic constitutive equation of the alloy at high temperature was established. The analysis of the model results show that the model can predict the plastic flow stress of TC18 titanium alloy under high temperature and impact load.