In thermal power plant, the use of boiler unit which produces steam helps to rotate the turbine to produce electricity. The boiler unit which consists of boiler drum converts feedwater into steam. The three types of boiler drum system are single element boiler drum, two element boiler drum and three element boiler drum. In thermal power plant the three element boiler drum is used. In the boiler drum, during the conversion of feedwater into steam, the level should be maintained and controlled properly. For controlling purpose the PID controller is used and the tuning of controller parameter controller is done manually. In the proposed method PID controller is replaced by adaptive controller where the tuning of controller will be made automatically. Thus the performance of the boiler drum level control system will be improved by three element method.