The chemical systems used in industrial applications are increasingly required to meet higher performanceand reliability requirements. The CSTR (Continuous Stir Tank Reactor) is an attractive piece of equipment in many industrial applications requiringdesired level and temperature characteristics due to its ease of controllability.The paper isdesigned to make a desired liquid level using both the LQR(Linear Quadratic Regulator) based Kalman estimation technique and 2 DOF (Degrees of Freedom)-PID (Proportional Integral Derivative)controller technique.The comparative results are presented with LQRand PID control strategies for liquid level control.Performance indices like Settling time (Ts) of a liquid level for a CSTR are evaluated using simulation experiments. In this paper a LQR based estimator gives better settling time than PID controller.The MATLAB was used for the simulation andperformance analysis of the control schemes was made. The simulation results justify the comparativeadvantage of LQR control method. © Research India Publications.