Provided in the utility model is a tool for measuring a center of a circle. The tool comprises: a scissors type connecting rod mechanism, which can be stretched and drawn back; a target mechanism, which is arranged at the center of the scissors type connecting rod mechanism and is used for cooperation with a total station for positioning; and four abutting elements, which are used for being abutting against a to-be-measured pipe fitting and are respectively arranged at positions, relatively symmetrical to the center of the scissors type connecting rod mechanism, of four connecting rods around the scissors type connecting rod mechanism. The provided measuring tool has the advantages of simple structure and convenient usage; the speed of measurement of the center of a circle of a pipe fitting can be substantially improved; and accuracy of measurement of the center of the circle of the pipe fitting can be effectively ensured.