Abstract: Requirements, key issues, and related works of data access control are introduced, and key elements and their interaction in data access control are analyzed in the paper. L-RBAC model is put forward based on lifecycle status of the product data and roles of the accessing user. After comparing push mode and pull mode in L-RBAC model, a permission calculation algorithm is given. L-RBAC model is implemented in a PDM project of an automobile company, as an example to testify the effectiveness of the model.