An on-line roll press hot forming process for a hot sheet/strip, which is used for the hot-bending forming of a hot steel sheet or strip steel, wherein a steel sheet or strip steel (1) that has incoming material that is hot is subjected to a slitting process and a hot-bending process and then becomes profiled steel (4) that has a specified shape; the hot steel sheet or strip steel is first slit-cut and then hot-bent, or first hot-bent and then slit-cut, or undergoes slit-cut and hot-bending synchronous processes, and during the slit-cutting process, the steel sheet or strip steel is slit-cut into strips; During the hot bending process, the steel sheet or the strip steel is continuously hot-bent and formed by means of deformation press roll sets (3). The described process may directly roll-bend the hot sheet/strip into a section of profiled steel, and longitudinally split said section into long strips of profiled steel or long strips of steel sheets; and the long strips of profiled steel may be used directly, or may be sent to a steel structure processing procedure to be welded into profiled steel. In using such a new production process, the cutting and edge processing steps required for processing a steel sheet to form profiled steel may be omitted, and the required welding process may be reduced or eliminated. The production cost is reduced and the production efficiency is increased.