Active disturbance rejection controller(ADRC) is a model-independent controller. It has good robustness and adaptability for the controlled systems with nonlinearity, large time delay, and high uncertainty. We notice that, although the previous work has focused mainly on its application in industrial engineering, the basic idea of ADRC also reflects very naturally the rational behavior of the decision maker in the face of dynamic optimization problems in economics and management science. The classical economic growth model is used as an example to demonstrate how to take into account the characteristic of economics so as to provide an effective mathematical tool for the analysis of a large class of dynamic problems in economics and management science.