Cable is widely used in engineering due to the good tensile performance. The cable tension is an important factor affecting the safety, which is necessary to be tested. Currently, the testing of cable tension mostly is calculated by the frequency method, which is to measure the cable frequency based on accelerometer or computer vision. Recently, the φ-OTDR has been developed, which can measure the frequency of several cables with just one low-cost communication fiber. It has a great prospect in the testing of cable tension. However, the coefficient of effective optical elasticity used to determine the sensitivity of the distributed fiber optical system is not unique in practice. To ensure the reliability of the data collected by φ-OTDR in the testing of cable tension, this study establishes a performance calibration platform for the distributed fiber optical system for cable monitoring by attaching the sensing fiber to the cable, and the midspan displacement of cable under different testing conditions are measured by using the digital image correlation method. The mid-span displacement is converted into the axial displacement of cable by analyzing the dynamic model of cable. Finally, based on the converted axial signal of cable and the phase collected by φ-OTDR, the performance calibration of distributed fiber optical sensing system is realized.