Small hydropower is one of the many types of new and renewable energy, which South Korea is planning to develop, as the country is abundant in endowed resources. In order to fully utilize small hydropower resources, there is a need for greater precision in quantifying small hydropower resources and establish an environment in which energy sources can be discovered using the small hydropower geographic information system. This study has given greater precision to calculating annual electricity generation and installed capacity of small hydropower plants of 840 standard basins by inquiring into average annual rainfall, basin area and runoff coefficient, which is anticipated to promote small hydropower resources utilization. Small hydropower geographic information system was also established by additionally providing base information on quantified small hydropower resources and analysis function and small hydropower generator status, rivers, basin, rainfall gauging station, water level gauging station etc., all of which were not provided by the domestic hydropower Resources Map System. Established GIS small hydropower energy system can be used to basic information for active uses of small hydropower energy which is scattered to the entire country.