In order to improve the lightning protection level of line catenary equipment and reduce the lightning shielding probability, the factor of protection angle is additionally considered in the calculation of lightning conductor height. Using the geometric relationship between protected equipment and lightning conductor position, the mathematical relationship between protection angle and lightning conductor erection position is deduced, and the corresponding mathematical model is established. By changing the erection position of the lightning conductor and adjusting the protection angle on both sides of the lightning conductor, the overall lightning shielding probability of the line is reduced. Referring to the OCS data of Zhun—Shuo railway, the lightning shielding probability of the line before and after adjustment is calculated and compared. It is found that the lightning shielding probability of the line after adjustment is reduced by 20.65%, which is close to the minimum lightning shielding probability calculated in theory. This method can effectively reduce the lightning shielding probability without increasing the cost.