Abstract: To traditional Si MOS field effect transistors, the transconductrance is proportional to the width length ratio of the channel. In this paper, the opposite phenomenon has been observed in graphene transistors. The graphene transistors with the same distance between source and drain electrodes and the same channel width have been fabricated. The transconductance with longer channel is larger. The reason is following. The channel area that covered by gate electrodes can affect the carriers in channel. The former is larger, the inductive latter is more. So, the transconductance is larger. The results and analysis are helpful to the comprehension and application of graphene transistors.