In order to solve the contradiction between the shortage of electric power corridors and power transmission capacity, large numbers of quadruple-circuits in one tower have been constructed in the Pearl River delta region. Taking Shunjiang 500 kV quadruple-circuit in one tower in Guangdong province as an example, this paper calculated the induced voltage and current of the maintained line. The results show that the induced voltage and current of quadruple-circuit in one tower are higher than those of double-circuit in one tower, the electrostatic induction voltage is up to 12% working voltage of operation lines, and the electromagnetic induction current is up to 6% current-carrying capacity of operation lines, which exceed the rated value of grounding isolators according to the IEC standard and the national standard. Furthermore, this paper analyzed the influence of transmission line maintenance arrangement and length on the induced voltage and current. It is an effective method to decrease the induced voltage and current of the maintained line by reasonably arranging the maintenance and setting the length of quadruple-circuit in one tower.