This paper first expounds the importance of project cost management, emphasizes the core position of quota standard in it, and then discusses the theoretical basis of metadata and its extensive application in information management. Metadata, as a standardized data description, provides a powerful tool for the fine management of engineering cost projects. The study further shows how the metadata is implemented in the actual engineering cost project. By constructing the metadata framework, while the information integration is optimized, the accuracy and efficiency of the cost estimation are improved. Specific applications include but are not limited to the standardization of bill of quantities, rapid response to project changes and intelligent retrieval of cost data. These application examples prove that metadata plays a significant role in improving the transparency and control effect of project cost management. In the conclusion section, it is pointed out that the introduction of metadata has brought revolutionary changes to the project management of engineering cost, which not only enhances the data interoperability and resource sharing of data, but also contributes to the establishment of a more scientific decision support system. Future research can further explore the combination of metadata with big data, cloud computing and other technologies, in order to promote the intelligent and modernization process of project cost management.