In order to decrease widthwise trimming loss of heavy plate, the metal deformation in width direction has to be controlled to ensure that the side-surface shape of plate is close to flatness. A method called large temperature gradient rolling (LTGR), which combines rolling with water cooling at the slab surface, is suggested to improve side shape of heavy plate. The process is studied by means of both simulations and experiments. LTGR process can correct the double bulge deformation effectively so as to avoid metal overlaps on the edge of plate by comparing with conventional rolling (CVR) process. The temperature gradient can result in deformation resistance gradient through the thickness of slab. The degree of width spread in the central region of the rolling piece increases under the condition of temperature gradient. It indicates that the deformation penetration deepens into the core area of the plate and the internal metal flow enhances. These results provided guidelines for further investigation and application on side-surface shape control of heavy plate.