The invention discloses a cloud computing technology-based unified maintenance and on-demand sharing method for power grid models. The method comprises the following steps of setting a model center system independent of each scheduling system, maintaining a power grid model within respective domination area through a terminal provided by the model center system by using each scheduling system, and sharing the power grid model with the other scheduling systems through the model center system; naturally combining the power grid models dominated by each scheduling system at the model center system without model splicing operation; automatically and immediately copying the power grid model update of the model center system to each scheduling system once the power grid model update is published; and acquiring the power model grid of the local area or the power grid models of the other areas or the whole network by utilizing a partial installation technology by using each scheduling system. The range of models required to be installed can be conveniently set according to the areas where the models are, stations where the models are, a voltage type, an equipment type and the like, so that immediate and synchronous updating is ensured, and the requirements of four major kinds of application of real-time monitoring and early warning, scheduling planning, security checking and scheduling management are comprehensively met.