A new idea of multilevel leakage protective system is proposed in this paper in accordance with the deficiencies covered in present leakage protective system used in underground low voltage distribution networks. The leakage is especially analyzed, which occurred from transformer secondary to general switchgear or from general switchgear to branch switchgear. The new leakage protective equipments which based on the new idea are also introduced here. Finally equipments are tested. The measuring results show that equipments can form a leakage protective system, the selective leakage protection of which has no time difference. Consequently, the level of safety for underground LV distribution networks is greatly improved.