Abstract: SCADA system is an automatic system for the production process automatic control and monitoring based on computer. It integrates the multi-function including production operation data acquisition and processing, alarming for various types of signals, device control, protection control and parameter adjustment together. A SCADA system for a large-scale oil tankfarm is composed of management layer, control layer and field layer. The paper introduces the structure, functions and features of each layer in details. And its feature is illustrated in field bus device, tank liquid level automatic metering system, industrial TV monitor system and SCADA system connecting with safe protection and fire protection. Combined with the operation and maintenance features of SCADA system for large-scale oil tankfarm, the point-to-point control for electrical valve which works based on real time feedback is presented. Suggestions to further improve the SCADA system in one-key operation of field facilities are given.