In this study, a plasma waveguide cladded by black phosphorus/dielectric multilayer structures was theoretically proposed. By numerically solving the dispersion equation with MATLAB, the performance curves of the effective refractive index, propagation length, penetration depth, and figures of merit of the waveguide could be simulated. According to the simulation curves, the performances of the waveguide positively and negatively correlated with the electron doping rate of the black phosphorus/dielectric multilayer structure and the dielectric thickness in the element layer. Compared with the same type of metal/medium multilayer structures waveguide, the black phosphorus/dielectric multilayer structures waveguide has a larger propagation length, a smaller propagation depth and a larger figures of merit in the mid-infrared and far-infrared bands. The waveguide is tunable and has excellent performance.