Drilling tool face measuring device and measuring method

The invention belongs to the technical field of oil and gas drilling, and particularly relates to a measuring device and a measuring method for a tool face of a drilling tool. The measuring device for the tool surface of the drilling tool is connected above a drill bit and comprises an outer cylinder which rotates synchronously with the drill bit; the coding disc is coaxially and fixedly arranged in the outer cylinder, and a plurality of coding holes with different sizes are uniformly formed in the coding disc in the circumferential direction in a penetrating manner; the valve block is used for blocking the coding holes, the valve block is coaxially and rotatably connected with the coding disc, and the valve block is constructed to enable at least one coding hole to be in an unblocked state; the gravity center of the weighting sensor does not coincide with the rotating axis of the valve block, and therefore the valve block always faces the same direction under the action of gravity. A pure mechanical structur