The route planning of transmission line should be carried out according to the geography and environment of the planning area.In view of the problems of many restrictive factors and difficult decision-making in traditional transmission line route planning, this paper proposes to use RS to acquire remote sensing image geographic information of planning area, and use GIS as data processing platform to quantify and integrate the geographic factors of transmission line route selection, and to establish the geographic information model of power supply line.An improved ant colony optimization (ACO) algorithm for path searching of transmission circuit is proposed, and the effectiveness and accuracy of the algorithm are verified by an example.The results show that the improved algorithm improves the efficiency of transmission line path search.This study provides a reference for the development of transmission line path planning in China.