Thermal process is typically nonlinear and uncertain. The control design becomes even more challenging in the presence of time-varying delay. Active disturbance rejection control (ADRC) has been shown to be an effective tool in dealing with real world problems of dynamic uncertainties and nonlinearities. In particular, to overcome the time-varying delay, time delay compensation based ADRC method is addressed. Contrary to Smith predictor, the most ef?cient feature of the proposed method is that it works without time delay models. The influence of time delay is regarded as the external disturbance, and is estimated by the designed disturbance observer. Validity of the proposed method in the cases of both constant delay and time-varying delay with unknown disturbance for the typical thermal process is verified by simulation results.