The invention discloses a structure of surface plasmon polaritons optical waveguide of nanowire arrays, which has low transmission loss and strong mode field limiting capability simultaneously. According to the waveguide structure, a cross section comprises a metal nanowire (1) embedded in a low refractive index medium (4) and two high refractive index medium nanowires (2 and 3) on the left and right side of the metal nanowire respectively. The metal nanowire and the two high refractive index medium nanowires close to the metal nanowire can remarkably limit the light field to low refractive index slot areas on the two sides of the metal nanowire, therefore the limit to two-dimensional sub-wavelength of the transmission light field is achieved and simultaneously, the transmission loss is still low. The optical waveguide structure overcomes the conflicts of the existing surface plasmon polaritons optical waveguide between the light field limiting capability and the transmission loss, and the transmission distance is further improved on the premise that the limitation of the sub-wavelength mode field is guaranteed. The waveguide can be used for constructing various passive and activeintegrated photonic devices and provides a possibility for achieving high density integrated optics.