Zirconium cladding absorbs hydrogen in the reactor, and the zirconium cladding will embrittlement in the Loss Of Coolant Accident(LOCA). The hydrogen-containing cladding is more likely to rupture in the process of accident or the subsequent treatment of accident, resulting in the leakage of radioactive products. In this thesis, residual plasticity of zirconium alloys with different hydrogen contents (0 ppm, 195 ppm, 315 ppm, 395 ppm) after simulated LOCA was studied, and the effect mechanism of hydrogen on residual plasticity of zirconium alloys during simulated LOCA was explored. The results show that the residual plasticity of zirconium alloy decreases with the increase of hydrogen content. The increase of hydrogen has little effect on the microstructure of zirconium alloy, and the effect of hydrogen on the microstructure of zirconium alloy is not the reason for the reduction of residual plasticity of zirconium alloy. one of the reasons why the presence of hydrogen leads to the decrease of the residual plasticity of zirconium alloy after simulated LOCA is that the increase of hydrogen leads to the increase of oxygen content absorbed by the prior-β phase after quenching, thus reducing the residual plasticity of zirconium alloy. Secondly, hydrogen may exist in the prior-β phase in the form of saturated solid solution or fine hydride brittle phase, which also leads to the decrease of the residual plasticity of zirconium alloy.