For the p and s polarizations, the surface plasmon polaritons (SPP) of magnetically tunable left-handed materials (LHM) and regular materials are investigated. The dispersion relations and characteristic lengths of SPP, including SPP wavelength, propagation distance of SPP and penetration depths of SPP in two mediums, are discussed in detail in different magnetic fields. It is shown that the properties of SPP can be controlled by the adjustment of effective magnetic permeability of metamaterials which is changed by changing the magnetic-field intensity. And the characteristic curves of SPP move to the region of short wavelength when the additional magnetic-field intensity increases.