The invention discloses a system and a method for meteorological drought monitoring and early warning based on power grid geographical information system. The system comprises automatic system database updating, drought data inquiry and index calculation, drought region chart generation and drought monitoring and early warning modules; the automatic system database updating module is used for obtaining the historical meteorological data of the weather bureau and realizing real-time and regular meteorological data storage; the drought data inquiry and index calculation module is used for calling the data in a drought monitoring database, performing drought index calculation and realizing multi-condition flexible inquiry and statistical calculation functions of meteorological elements; the drought region chart generation module provides diversified product expression forms such as a grid map, a line chart and a table; the various index modules are combined with power grid tower information and realized on the GIS, respectively, and tower drought grade monitoring and early warning are provided; if the tower is not a drought occurring point, the system has no early warning; if the tower is the drought occurring point, the system provides early warning. The system is capable of effectively improving the drought disaster resistance of the power grid.