A hydraulic steel strapping machine for strapping a steel strip around a package, including a clamping and cutting section and a tensioning section. An objective of the present invention is to minimize the weight and the volume of the steel strapping machine. The clamping and cutting section comprises a clamping cylinder, disposed on a top position of a front end of the hydraulic steel strapping machine along a Z direction and supported by a support frame, for driving a linkage mechanism. A cylinder pin is disposed in the linkage mechanism along a X direction and is sleeved by a lifting lug fixed onto a bottom surface of a piston of the clamping cylinder. A pressing part is sleeved around the cylinder pin, a cutter a return spring and a transverse cutter are disposed below the pressing part. The linkage mechanism comprises two groups of connecting rods.