With the continuous development of digital information in the field of power grids, the pro-portion of unstructured data in the total amount of information is increasing. At the same time, there is a lack of uniformity in the management of unstructured data in many applications. In order to improve the a-bility of data management and the utilization ratio of digital assets,in this paper, an unstructured metadata management technology based on common model technology is proposed. The unstructured metadata re-sources are sorted out, and the corresponding model is designed. A reasonable unstructured metadata management method is designed. In order to protect the security of data, an encryption algorithm is pro-posed. The feasibility and practicability of the method are proved by the application.