A cable curvature measuring method comprises the following steps: S1: acquiring the distances between any three adjacent points and an observing points on a cable curve, and calculating the initial curvature rho' on the cable curve by utilizing a three-point method according to the three distance information; S2: acquiring the image information of the cable curve, and obtaining the compensation curvature rho'' according to the image information; and S3: obtaining the accurate curvature rho according to the initial curvature rho' and the compensation curvature rho''. According to the cable curvature measuring method, the cable curve information is extracted from a cable curve image. According to the cable curvature measuring method, the cable curve information is extracted from the cable curve image, the cable curvature obtained by a laser ranging method can be compensated according to the information, the all calculations are implemented in a digital processing unit, so that the cable curvature measuring method has the advantages of high precision, strong instantaneity, high processing speed, and long-distance measurement under the complicated topography.