The cable tension and stiffness of a cable rod hybrid driven parallel mechanism were analyzed. Considering the unidirectional force of the cable and the bidirectional force of the linear motor, the mechanical analysis of the position and posture of the moving platform of the mechanism was carried out, and the relationship between the cable tension and the thrust of the linear motor was obtained. The stiffness matrix model of the parallel mechanism was derived by combining with the definition of stiffness, the relationship between the structural parameters of the mechanism and the tension of the flexible cable; the stiffness evaluation index was obtained through MATLAB simulation. The distribution law of the stiffness in the working space of the mechanism was summarized.