The invention discloses a GIS-based gridding power transmission line operation and maintenance difficulty quantitative evaluation method, which uses power transmission line operation and maintenance difficulty evaluation data of each grid unit, adopts an entropy weight method as a weight calculation model, combines with GIS system spatial analysis, formulates power transmission line operation and maintenance difficulty grades of different operation and maintenance difficulties, can be used for objectively grading a final operation and maintenance difficulty value, avoids the subjectivity caused by manual grading, formulates different operation and maintenance difficulty intervals, and enables the operation and maintenance personnel to be able to query the operation and maintenance difficulty range of each sample specifically according to the grading intervals. In addition, the GIS-based gridding power transmission line operation and maintenance difficulty quantitative evaluation method provides a power transmission line operation and maintenance difficulty quantitative evaluation reference based on geological positions for a power grid operation and maintenance patrol inspection department by means of geological information visualization service offered by the GIS, provides guidance suggestion for a power grid operation and maintenance department in the aspects of operation and maintenance management, personnel assignment and resource optimization, avoids excessive manpower and material resource investment, and saves cost.