The invention relates to a building method and system of a cloud platform based on BIM and GIS cooperative work. The invention belongs to the technical field of data processing, and is characterized in that the method comprises the steps: 1, building a cloud platform: enabling the cloud platform to comprise a public cloud platform, a private cloud platform, and a unified cloud management platformwhich carries out the data interaction with the public cloud platform and the private cloud platform; 2, establishing a hydropower engineering collaborative management framework based on BIM and GIS,wherein the hydropower engineering collaborative management framework comprises a data storage processing part, a business logic part and a visual interaction interface; and 3, performing remote cooperative work based on the BIM and the GIS. The invention aims at the defects of the traditional information exchange and management working mode. The invention provides a management method for realizing data sharing, convenient communication, tight cooperation, effective management and high visualization degree, the practicability is strong, the collaborative design efficiency is greatly improved,the management level and the design quality are improved, the cost is saved, and the requirements of all parties can be met.