The general form of nonlinear system has been studied. It is concluded that under general conditions the differential equation of the nonlinear system and the nonlinear state feedback control are both linear with respect to their control variables if the system is globally linearizable by this nonlinear state feedback control. Global linearization via state transformation has been considered. Sufficient conditions expressed in form of the given system have been obtained, which are simple in form and easy to check. Finally, the simultaneous linearization by state feedback and state transformation and the synthesis problems have been discussed.