This paper discussed the necessity of technique reformation of capacity expansion for the 3.52 km transmission lines directly connected Qinshan 500 kV combined switch station, and analyzed the feasibility of the replacement of the 4×AF (SZ) S4A-400/45 augmented capacity conductor for the 4×LGJ-400/35 conductor. The parameter matching performance between the augmented capacity conductor and the 4×LGJ-630/45 conductor of Qinyou 5415/Qinquan 5416 newly built was also studied. The technique reformation scheme of capacity expansion can provide references for the power transmission capacity increase in the developed area where there is not enough transmission line corridors.