Abstract: Based on features of Object-Oriented Engineering Database Management System (OOEDBMS), we define the model of its data language—OSQL including DDL & DML and analyze its functions, and then we intreduce the structure and design of our CAD center's OOEDBMS and OSQL based on it and discuss some important methods we use in their implementatinon, such as the abstract data type operation, complicated semantic expressing, working area design, etc.. Finally, the direction of further research for OSQL is given.