The output characteristics and the electronic behaviour of a quantum wire transistor (QWT) with a 1DEG channel have been simulated. The electron transport processes in the QWT are mainly influenced by quantum mechanical effects. A coupled microscopic/macroscopic simulation algorithm is used to calculate the electron density distribution in the electron gas under consideration of the confinement of the electrons. This algorithm includes the self-consistent solution of the Poisson and the Schrödinger equation.