The invention discloses a comprehensive monitoring and early warning system based on meteorology and a power grid GIS and a method thereof. The system comprises a data layer and an application layer. The data layer consists of a meteorological database, a power grid GIS database, and a production and operation database. The application layer includes a meteorological monitoring module, a meteorological early warning module, a power grid weather module, an information display module, and an auxiliary decision-making module. The meteorological database, the power grid GIS database, and the production and operation database carry out communication mutually; and the meteorological monitoring module, the meteorological early warning module, the power grid weather module, the information display module, and the auxiliary decision-making module carry out communication with the meteorological database, the power grid GIS database, and the production and operation database respectively. According to the invention, meteorological monitoring information like the temperature, wind direction, and wind speed and the like of important power equipment like a transformer substation, a transmission and transformation line, and a tower can be gotten in real time; and visual meteorological real-time data can be provided for the power grid. Meanwhile, prediction and disaster early warning information of the typhoon and thunder and the like can be provided every 12 hours in the next seven days.