The present invention discloses a mechanical sealing ring friction force measurement device and method. The measurement device comprises a loading and force measurement module 2, a displacement measurement module 3, a rotary table module 4, a control module 5, a frame-shaped pedestal 1, a supporting plate 6 fixed at the top of the pedestal 1 and a workbench 7 fixed in the pedestal. The friction force measurement method adopts two modes of the working condition state measurement and the offline state measurement. The mechanical sealing ring friction force measurement device adopts a vertical loading measurement structure, and a loading head adopts a floating loading structure, so that the problem that the loading force and the motion direction generate the unbalance loading, is avoided. On a rotation working condition and at different corner positions, a force measurement sensor and a displacement sensor measure the force and the displacement simultaneously, and the relation among the force, the displacement and the time is determined by a control system. The advantage of the present invention is that the work state of a mechanical sealing ring during an actual work process can be simulated to load and unload a rotating seal ring.