A unique graphene-based hybrid plasmonic waveguide (GHPW) is proposed with a relatively high figure of merit (FOM) and long propagation length () in the far-infrared (FIR) region. The proposed waveguide is combined of a high-index cylindrical dielectric in the coordinate origin, a low-index dielectric strip, and a monolayer graphene that set are surrounded by rectangular cube. The modal features of the graphene surface plasmon polariton (SPP) mode are investigated via the finite element technique. Finding results display that a propagation length of and a figure of merit can be obtained by tuning the dimensions of the waveguide geometry and the different materials. Therefore, propagation properties of the proposed waveguide improve significantly by changing the materials type of dielectric strip and cylindrical dielectric. According to the present findings, the GHPW can be used in the …