With the appearance of MBD/MDE technology, the full three-dimensional model has become the sole basis for the manufacturing process of products.However, the PDM system based on the traditional relational database is not only difficult to meet their data format requirements, but it is also inadequate in many issues such as the highly concurrent reading and writing, the high-efficiency storage and access of mass data, the scalability and high availability of database.The paper analyzes advantages of the non-relational database NoSQL, as well as the creation concept of the PDM Product Structure Tree.It discusses the data storage structure of PDM data in MongoDB combining the structural relation of Product Structure Tree and the features of MongoDB, which breaks the traditional model of table structure in relational database.We establish a new model of data storage in PDM based on NoSQL, in order to capture the ancestor-descendant relationship in Product Structure Tree and maintain the Product Structure Tree more easily.