The utility model provides an accurate measuring tool of steel bow member cutting angle for tunnel support, movable rod sliding connection are inside the dead lever, and the movable rod has dug a plurality of fixed orificess, and a plurality of fixed orificess distribute along the axis direction of movable rod, and the one end that the movable rod was kept away from to two dead levers is articulated each other, is connected with the calibrated scale between two bracing pieces, the calibrated scale is convex, and the calibrated scale is protruding to the one side of keeping away from the dead lever, and wherein one end and two dead levers of chaining pin are articulated, and the other end of chaining pin rotates along the calibrated scale, and the chaining pin passes through the buckle andconnects in the calibrated scale. An accurate measuring tool of steel bow member cutting angle for tunnel support, through the precision measurement to the steel bow member for batch production production can be realized to the steel bow member, has made things convenient for the cutting and the installation of steel bow member.