The invention relates to a method and a system for evaluating a lightning protection project of a power transmission line containing various lightning protection measures. The method comprises the following steps: 1) calculating technical effect quantitative index values of different lightning protection projects by using an established technical effect quantitative evaluation index system according to various basic data and external meteorological condition normalization adjustment results of different statistical time sections before and after different lightning protection project treatmentmeasures are implemented on a collected target power transmission line; 2) scoring the technical effect quantitative index values of different lightning protection projects according to the technicaleffect quantitative index scoring standard and the technical effect quantitative index values obtained through calculation; 3) quantifying the index score condition through the technical effect of the lightning protection technical improvement project, and measuring the performance condition of each lightning protection technical improvement project in combination with the technical improvement target of the lightning protection technical improvement project; and 4) adjusting lightning protection treatment measures in each lightning protection technical improvement project according to the performance condition of each lightning protection technical improvement project. The method can be widely applied to the field of power grid operation safety assessment.