A right-angle valve drilling alignment device is characterized in that hinge shafts are respectively mounted on the opposite peripheral surfaces of a disk drilling die plate. The axes of the two hinge shafts coincide with the same diameter line of the drilling template. Right connecting rods are mounted on the two hinge shafts. A correcting rod is mounted between the right ends of the two connecting rods. Adjusting nuts are mounted on the connecting rod on the outer side of the correcting rod. Four round die holes arrayed in a square are formed in the drilling die plate. The circle centers of the four round die holes are on the same circle. The circle is concentric to the drilling die plate. The included angles between the connecting line between the circle centers of the two opposite round die holes and the axes of the hinge shafts are 45 degrees. The problem that when a right-angle valve bolted hole is processed, the operation of determining the positions of valve flanges one by one is complicated is solved, and the right-angle valve drilling alignment device is especially suitable for processing four bolt holes in a right-angle valve flange.