In this research, an educational automatic purification facility of waste water is designed. The system has four functions which are filter tank, aeration tank, reactor tank and ultraviolet sterilization tank, and is embodied by PLC(Programmable Logic Controller), DC motor, solenoid valve, squirt gun, propeller, profile, switch, sensor and so on. Also, the system is designed and manufactured based on knowledges which are obtained from college education. The study is emphasized on "learning by doing". From this case study, students can increase their originality and adaptability for related industry. Also, the technique can be initiated industry if needed.