An Automation is the utilization of different control techniques for operating equipment’s such as operations in factories, aircraft and other applications with reduced human power. The filling process is a mission performed by a machine that fills liquid products such as liquid or cold drinks. Traditional bottling methods include placing bottles on a circular disc and filling only one bottle at a time. In this proposed work, it has been designed and implement liquid filling machine system for different sized bottles by using PLC. This idea will become a great solution for small and medium scale industries because they can produce different types of products at different heights in a single conveyor line. Here sensors act as the input device. PLC acts as the real time decision maker, so it makes the decision according to the control logic fed into it based on the respective input signals. PLC actuates the field instruments to perform specified operation in accordance with the program. Where the liquid filling machine system includes design and implement prototype of a flat belt conveyor with dimensions and automatic process for liquid filling machine using the solenoid valve and sensors which gives the appropriate information to control unit then design the controller using PLC. The PLC plays important role to implement automatic filling process by using PLC programming software and ladder diagram language. It was found that the liquid filling machine using PLC is less operational cost and less power consumption than the traditional control systems, in addition more flexible and time saving.