The present invention relates to a geographical information system used for electrical power system, wherein the system comprises a human-computer interface module, a basic geography data module, a elementary graph operation module, a view display module, a electric network device management module, a power distribution network equipment input module, a power distribution network equipment attribute maintenance module, a electric power network topology maintenance module, a line maintenance module, a underground pipe network management module, a search statistical form module, a pole tower detailed statement management module, a network topology maintenance module, a electric network topology analysis function module, a single line figure management module, a scheduling system drawing management module, a graph input-output function module and a system administration module, wherein the human-computer interface module connects with every other module mutually. Compared with prior art, the present invention is provided with definite openness, normality, flexibility, expandability, high security and economy, and the like.