Abstract In this paper, a quick identification method based on the short time record of input-output data is introduced for joint state and parameter estimation of nonlinear continuous-time systems. The method can then be used for on-line monitoring the system with unknown parameters. An application way of the method to main-steam temperature control of a thermal power plant are developed in the framework of model reference adaptive control system (MRACS). Simulation studies on a super-heater model have been carried out to demonstrate the effectiveness of the proposed method.