The invention relates to the technical field of ore grinding control in a concentration plant, in particular to an intelligent hierarchical control method and a control device for ore grinding in a concentration plant. The control method comprises the following program processes: controlling system initialization; judging whether ore feeding quantity control is implemented or not; implementing ore feeding quantity PID control; judging whether ore water feeding control is implemented or not; implementing the ore water feeding control; judging whether ore water discharging control is implemented or not; implementing the ore water discharging control; judging whether cyclone inlet pulp density and water replenishing cascade control is implemented or not; judging whether pump sump liquid level control is implemented or not; implementing the pump sump liquid level control; judging whether the ore grinding process is finished or not; finishing the ore grinding process; judging whether to return or not; and carrying out interconnected control on each processing device. The device comprises an upper computer, a lower computer, a detecting instrument and an executing mechanism. The invention enables the system to have the characteristics of high control accuracy, high regulating speed, strong interference resistance, stability, reliability and the like, accurately regulates the operating parameters in real time, and improves the working efficiency and the product quality of grinding classification.