Abstract: Siemens 828D CNC system is a full digital high-end CNC system . This paper mainly studies the OPC UA of Siemens machine tool itself, and develops a client that conforms to the OPC UA specification. Using the client to obtain the information of variables, the data in OPC UA server is collected through the program developed by python, and the collected data is stored in MySQL database after processing. The results show that on the basis of the data table, the single table storage is reduced by using the data table differentiation function, and the read-write separation architecture of the database is adopted to avoid data blocking, so as to improve the performance of the database.