The invention relates to a double-circuit overhead power transmission line double-T wiring tower and a wiring structure thereof. The wiring tower comprises a vertical steel tube tower which is provided with seven layers of cross arms from the top to the bottom. The second, third and fourth layers of cross arms are arranged on the tower surface of a main circuit I side and are main circuit I cross arms. The fifth, sixth and seventh layers of cross arms are arranged on the tower surface of a main circuit II side opposite to the main circuit I and are main circuit II cross arms. The tower surface of the suspension external side of the main circuits I and II is provided with six cross arms from the top to the bottom, wherein the cross arms corresponding to the second, third and fourth layers of cross arms are main circuit I outlet wire cross arms, and the cross arms corresponding to the fifth, sixth and seventh layers of cross arms are main circuit II T-shaped outlet wire cross arms. Common-tower double-circuit reverse double-T lower wiring is realized so that problems of high difficulty, high cost and high influence on surrounding environment of double circuits in realization of double-T lower wiring while suspension can be solved.