Abstract: In order to calculate cable tension more precisely with the help of modern measuring technology, a new method is proposed in this paper based on cable segment's static analytical formula. After the coordinates of three points on a cable are measured, cable tension can be calculated by solving the corresponding non-linear equations. The precise laser measuring instruments can measure many cables from one site quickly, and therefore the effectiveness of this new method is guaranteed. Moreover, it overcomes the shortcomings of the comnonly used methods, whose results are affected by the end condition of cable. Numerical example indicates it is precise enough even if the cable's elasticity is neglected, and the cable tension error resulting from measurement and cable vibration is ignorable. The application to one cable-stayed bridge has verified the precision and practicability of the present method. It can be used during the construction and the service of cable-stayed bridge, suspension bridge, cable-suspended roof and other cable structures, whenever the cable is static or vibrating with small amplitude.