The main purpose of heat ex-changer system is to transfer heat from hot fluid to cooler fluid, so temperature control of outlet fluid is of prime importance. In this work different controller such as PID controller, Feedback plus feed-forward controller and a ratio controller is developed to control the outlet temperature of the shell and tube heat ex-changer. The developed ration controller has improvement in the overshoot and settling time over the classical controller and feedback plus feed-forward controller. Control accuracy is also good as steady state error is becomes zero.