Abstract: The heat treatment tests of super thick specification 13MnNiMoR were carried out with different normalizing temperatures. The microstructure and mechanical properties of the test steel in different heat treatment processes were measured and determined by means of metallographic microscope, tensile testing machine and impact testing machine. The results show that normalizing temperature has little effect on the strength and properties of the test steel. At 860 ℃normalizing+650 ℃tempering process, the low-temperature impact toughness of the test steel is obviously better than that of 930 ℃normalizing+650 ℃tempering process.The main reason is that the austenite grains in the normalizing heating process can be refined at a lower normalizing temperature.In the subsequent air cooling process, fine Ferrite grains are obtained.Thus, a large number of ferrite grain boundaries are obtained at room temperature, which greatly improves the ability to absorb impact energy.