Gray iron was hot-compressed on a Gleeble 3500 machine. The effect of hot compression on mechanical properties of gray iron was studied. The result shows that gray iron with the sandwich structure of graphite and ferrite matrix is prepared after more than 45% reduction of hot compression. The mechanical properties of 80% hot-compressed gray iron are significantly enhanced: tensile strength from 117MPa to 249MPa, and total elongation from 0 to 5.2%. The tensile fracture surface presents ductility characters after more than 45% reduction of hot deformation. The increase of the strength and ductility of the hot-compressed gray iron is caused by delamination toughening.