The invention provides a quantitative evaluation method for the activity of a blast furnace hearth. The activity of the hearth is represented by the working activity index of the hearth, and the working activity index of the hearth is the ratio of the central temperature of a dead coke stack of a blast furnace to the temperature mean value of a thermocouple on each layer, at the sidewall of the hearth. Compared with the traditional method, the temperature mean value of the central thermocouple on each layer, in the hearth and at the bottom, is replaced by virtue of the central temperature of the dead coke stack, and the temperature state and the change thereof of the dead coke stack can be much directly reflected, so that the liquid permeability and air permeability of the dead coke stackare fed back at the first time. The quantitative evaluation method for the activity of the blast furnace hearth overcomes the defect of lagged and distorted calculation result of a traditional model,and provides more scientific judgement basis for realizing rapid and accurate quantitative evaluation for the active state of the hearth.