The precision cable drive is a flexible frictional transmission method in which power is transmitted from drive capstans to a driven pulley by a properly preloaded transmission medium. Owing to its many advantages, such as lightweight, high efficiency, and simplicity, it has been widely used in the field of lightweight electro-optical tracking. Cable tension is an important design parameter that can effectively regulate the transmission characteristics of the precision cable drive. However, accurate measurements of cable tension in highly confined spaces are difficult to make with the existing tension meter method. Therefore, a revised three-point-bending method was proposed in this paper. Parametric sensitivity was investigated to evaluate the relationship between the transmission characteristics of the drive and cable tension. Furthermore, a revised model for measuring cable tension that included bending rigidity was established. To validate the proposed theoretical models, a series of experiments were performed with two types of cables and three kinds of measuring spans. The test results reveal that the tension deviation could can be reduced to 5 N by using the proposed method, which is considerably lower than that obtained with the tension meter method reported in the literature. The revised method can meet the requirements of cable tension measurement in a precision cable drive system.