The invention relates to rolling method used to solve continuous casting small square billet porous shrinkage cavity. It includes the following steps: heating, high pressure water de-scaling, rolling and cold controlling. Its features are that in heating, hot section temperature is increased to 1250+/-20 degree centigrade and remained for 65+/-5 minutes; before rolling, the pressure in high pressure water de-scaling is controlled at 70-150MPa; rolling temperature is controlled at 1020-1060 degree centigrade. This method can make the porous shrinkage cavity of the small square billet center seam.