Abstract: In the concept of dynamical linearization of non-linear system proposed by the author, the dynamical linearization is only formal, but not a real linearization. From the linearization procedure, a new approach of system identification that is on-line real time modeling and real time feedback control correction can be found. The modeling and real time feedback control are united in the identification approach, and the pattern of parameter adaption is broken up. The structure adaptation of control system is achieved, so the complex modeling steps are avoided. The objective of this paper is to introduce the approach of unity of modeling and control.