In this futuristic era, Ultrasonic sensor has been successfully used in non destructive testing and also widely used in medical imaging. But in real life now, Ultrasonic sensor has been use in repellent the rat away from the house. Indeed, this project is to develop the electronic repellent and suitable system to drives the rats away effectively .For the scope of this final year project, the pests are the rats. They are repelled by ultrasonic frequency in the range of 30 kHz to 50 kHz. However, all pests do not react at the same ultrasonic frequency. So this project is to develop a product that can chase a rat effectively using ultrasonic sensor without harm anyone even the human. This project is containing the main unit and small unit. For the main unit it contains RF receiver and microcontroller. Meanwhile, for the small unit it’s contains motion detector sensor, RF transmitter and Ultrasonic circuit. The microcontroller is to control the sequence of this project after it gets the signal from RF transmitter and receiver. The other Ultrasonic repellent has their advantage and disadvantage. So, this project is to developing the disadvantages of the old Rat Repellent product.