Abstract: To assess impact of construction of power transmission and transformation projects on habitat fragmentation, an evaluation indicator system for habitat fragmentation is built in this paper, from three aspects: habitat quantity and area, habitat edge characteristics and habitat isolation status． ArcGIS and Fragstats are the major tools used, typical power transmission and transformation projects are selected． Comparative analysis of habitat fragmentation before and after project construction was done． The construction of power transmission and transformation project is found to lead to a slight increase in habitat fragmentation degree of the whole evaluation area and each type, as reflected in increased number of habitat patches, decreased average patch area, enhanced boundary effect, and slightly increased habitat isolation degree． Changed rate of each indicator before and after construction of power transmission and transformation project is extremely low, with basically no impact on habitat structure．