Abstract: The paper proposed a design scheme of centralized lubrication system with distributed type based on RS485 bus. It gave general structure of centralized lubrication system with distributed type, and detailedly introduced design of interface circuit of RS485 bus of oil supply terminal and communication protocol and communication program between main control cabinet and oil supply terminal. The actual application showed that the system can meet with demands of oil supply by need, independent of each other, centralized monitoring and easy extension.