Abstract: To ensure the safe use of high pressure cylinders with the risk of hydrogen embrittlement, the chemical composition analysis, mechanical property testing and hydrogen embrittlement resistance test of 34CrMo4 steel for high pressure cylinder from two domestic steel mills were conducted. The hydrogen embrittlement resistance and influence factors of 34CrMo4 steel from different steel mills were studied and compared. The results show that the main chemical composition of 34CrMo4 steel from different steel mills was basically the same. Due to relatively big differences in the content of the gas elements O, N and H, the harmful elements P and S and the trace elements (V+Nb+Ti+B+Zr), in the grade of non-metallic inclusions, and in the impact properties of the steel, the tensile strength for passing the hydrogen embrittlement test was different, which was 901 MPa and 968 MPa, respectively. The corresponding maximum hydrogen embrittlement indexes were 1.93 and 1.92, respectively. For the high pressure cylinders with the risk of hydrogen embrittlement, the maximum tensile strength and the yield ratio of the materials should be limited. In addition, the content of harmful elements P and S and that of the trace elements (V+Nb+Ti+B+Zr) should be limited.