In the recent world as technology grows, the automation sector is also growing because it controls the process automatically without the need of human person. In this paper, we discuss about the SCADA System which stands for supervisory control and data acquisition. It is a powerful system for industrial automation and supervisory monitoring. This system collects the information from the sensors and the data from a process that is analyzed in real-time by RTU or MTU. This paper also gives information about SCADA generation i.e. monolithic, distributed, networked and web based. SCADA have two types of architecture one is hardware and other is software. SCADA systems are essential to a wide range of industries and are broadly used for the controlling and monitoring of a process like data like flows, currents, voltages, pressures, temperatures, water levels.