The invention discloses a state quantity detecting system in conditions of typical defects of a high voltage electric cable. Currently no state quantity detecting system in conditions of typical defects of the high voltage electric cable is available, and no research on detection difference and effectiveness of all kinds of state detection technological means for different defect types is conducted. The state quantity detecting system comprises a voltage boosting system, a current increasing system, an electric cable model and a detection system, wherein the voltage boosting system, the current increasing system and the electric cable model are used for simulating electric cable operation condition; the electric cable model comprises a main loop circuit, a middle connecting head test loop circuit and a terminal test loop circuit; the two test loop circuits are used for performing test operation in an independent manner or in a joint manner, and the main loop circuit provides running state reference; detection modes adopted by the detecting system comprise a partial discharge detection mode, a temperature detection mode and a grounding loop current detection mode. Via simulation tests conducted via the state quantity detecting system, detection difference and effectiveness of all kinds of state detection technological means for different defect types can be assessed, and electric cable state quantity change rules in different load conditions can be researched in the partial discharge detection mode, the temperature detection mode and the grounding loop current detection mode.