Abstract: There are asymmetric un-gated regions that give rise to unequal assess resistances between the gate and the source/drain (S/D) electrodes in the graphene field effect transistor (GFET), which has a certain effect on the performance to the GFET. For the first time, in this paper, when the source and drain electrodes exchanged, the output characteristics, transfer characteristics and transconductance of the asymmetric GFET are measured respectively. The influence mechanism resulting from the asymmetry Source and Drain is analyzed by using the common source circuit model with source negative feedback resistor and the total resistance equation of graphene channel. It provides a useful reference for preparation and testing of GFETs and other nanostructured material transistors.