Abstract: By the reasonable composition design and uncompromising controlled rolling and controlled cooling process, 120 mm thick Q460 steel plate was developed successfully. The effects of rolling process on the microstructure and mechanical properties of the plate were investigated. The results show that under different process conditions, the basic microstructures of the tested plate all consisted of ferrite and pearlite and showed an obvious band-like shape in the core. The strength of the steel plate was slightly improved by the increasing cooling intensity after rolling while the toughness was not ameliorated. The ferrite and pearlite microstructures were obviously refined, the band-like microstructure amount decreased, and the toughness of the steel plate was significantly improved meanwhile the strength kept unchanged by the increase of the intermediate holding thickness.