Abstract: The physical simulation process of Q420 ultra-heavy steel plates 100 mm thick was carried out. The optimized production technologies of Q420 steel plates with different quality levels were obtained by analyzing the effects of deformation and heat treatment processes on the microstructure and properties of Q420 steel plates. The results showed that the steel plates rolled with TMCP(thermo-mechanical control process) process have better properties and finer ferrites than those rolled with UPR(ultra-heavy plate rolling) process. After heat treatment, the plasticity and toughness of the rolled plates are greatly enhanced, with the finer ferrites obtained, but the strength of the plates decreases. The steel plates normalized at the same temperature after different hot-rolling processes have little differences in the properties, showing the rolling processes have little impact on the microstructure and properties of the normalized plates.