A cable supporting assembly for use in a rack system includes a connecting device, a cable supporting member, a first mechanism, and a second mechanism. The cable supporting member is movably mounted on the connecting device. The first mechanism is arranged at one of the connecting device and the cable supporting member, and the second mechanism, at the other. The first mechanism and the second mechanism can connect with each other to keep the cable supporting member at a predetermined position with respect to the connecting device. The cable supporting member can be moved to a first position or a second position with respect to the connecting device when the first mechanism and the second mechanism are not connected with each other.