Direct-reading type calipers for measuring ovality of pipeline

The invention provides a pair of direct-reading type calipers for measuring the ovality of a pipeline. The pair of direct-reading type calipers comprises a calipers body which comprises two calipers legs with the ends hinged to each other through a hinge pin; a rotation angle sensor used for detecting relative rotation angle signals of the two calipers legs is arranged on the hinge pin, a digital display box is arranged on one calipers leg, an integrated circuit board is arranged in the digital display box, a microprocessor used for processing and calculating the angle signals sent by the rotation angle sensor and obtaining a space value between the ends of the two calipers legs is integrated on the integrated circuit board, and a display screen connected with the microprocessor through signals is arranged on the digital display box. The direct-reading type calipers have the advantages that when the direct-reading type calipers are clamped on a bent pipe or an elbow of the pipeline, the number is read without the requirement for taking the direct-reading type calipers out of the pipeline, the angle value is directly read, the calipers legs of the calipers are fastened at largest distance points, and the phenomenon that due to the fact that the distance between the two calipers legs changes, the accuracy of the value is influenced is avoided. An electronic mode and a mechanical mode are used for measuring the angle and errors are reduced.