As an important part of power system, distribution line directly affects the stability and reliability of power supply. However, the distribution line is easy to be affected by the environmental conditions, in which the lightning-induced voltage is the main factor causing the lightning fault of overhead distribution lines. In this paper, the Agrawal model is selected and the FDTD algorithm is used to calculate the lightning-induced voltage of the overhead line. The effectiveness of the algorithm is verified by a detailed example. The influence factors of the lightning-induced voltage are analyzed. The results show that this method can accurately calculate the lightning-induced voltage of the overhead line, and the analysis results provide a theoretical reference for lightning protection and insulation design of overhead power lines.