The invention discloses a control method of a single-rack steckel mill for reducing the final pass speed of rolling pieces. When the pressurized rolling of the rolling pieces is finished with odd passes, the rolling pieces achieve target thicknesses, a roll gap is opened, and the rolling pieces return to the front of the single-rack steckel mill and jump the single-rack steckel mill at technically required speed, i.e. final pass speed less than 1.5 m/s; and when the pressurized rolling of the rolling pieces is finished with even passes, the rolling pieces achieve the target thicknesses, the roll gap is opened, and the rolling pieces pass through the single-rack steckel mill at the technically required speed, i.e. the final pass speed less than 1.5 m/s so as to finish rolling. The invention reduces the final pass speed to the minimum 0.5 m/s by modifying the control process of the single-rack steckel mill, thereby realizing that the single-rack steckel mill reduces the final pass speed, and preventing an oil film bearing of the single-rack steckel mill from being burned; in addition, the invention also discloses a steel-grade rolling process which can also automatically reduce the final pass speed of the rolling pieces passing through the single-rack steckel mill according to requirements and meet the requirements of certain special control and cooling processes.