The invention discloses a device for measuring the permeability coefficient of rock material under the action of seepage-stress coupling, which comprises a triaxial pressure chamber balance system, a permeability coefficient acquisition system and a data acquisition and processing system, wherein the triaxial pressure chamber balance system loads samples axially or laterally through different stress paths; the permeability coefficient acquisition system is connected with the triaxial pressure chamber balance system so as to realize the determination for the quality of penetrating fluid of rock material sample; and the data acquisition and processing system regularly acquires the quality of penetrating fluid of rock material, calculates penetration flow and permeability coefficient, and draws a relationship curve of the permeability coefficient and time, and simultaneously, the data acquisition and processing system also forms a data format of the quality, the penetration flow and the permeability coefficient for storage and display. Such a measurement device can measure the permeability coefficient, as time and stress change, under different stress loading paths, has simple operation and reliable result, and can display the result visually. The invention also discloses a measurement method adopting the measurement device.