In order to evaluate the stability of a camera robot, a new stability performance index with combination of force and position based on the determinations of the cable tensions is proposed in this paper. First, two position factors based on the kinematic model of the camera robot are presented to show how far the specified position is away from the center of the horizontal plane at which the specified position locates within the workspace and how far the specified position is away from the top of the workspace, respectively. Then, two force factors are also developed to show the distributions of the minimum cable tensions in the specified region of the workspace. Furthermore, the stability performance index is described using the weighted method. And subsequently, the stability workspace is designed with the stability performance index. Finally, a robustness workspace with the external wrench is selected to demonstrate the effectiveness of the stability performance index above for the camera robot. Simulation results show that it is suitable to employ stability performance index to evaluate the stability of the camera robot.