Thermal oxidation process was performed on TC4 alloy for 10 h at the temperature of 700 °C. The static and dynamic mechanical behaviors of the thermal oxidized TC4 were investigated by quasi-static compression, nanoindentation and split Hopkinson pressure bar impact tests. Moreover, the micro-morphology of the oxide layer after impact tests was analyzed by scanning electron microscope (SEM). The results indicate that after thermal oxidation the static mechanical properties of TC4 is improved and its strain rate hardening effect is enhanced. Under a relatively low strain rate, the oxide layer could increase the plastic deformation ability of TC4. At a large strain rate, however, the oxidation layer reduces its plastic deformation ability. Through fitting of the impact test data and constitutive model correction, the Johnson-Cook (J-C) constitutive equation of the thermal oxidized TC4 is obtained. Compared to experimental results, the correction and experimental curves have a good agreement in the plastic deformation region.