One-dimensional photonic quasi-crystal (1D PQC) has continuously shown their superiority in the fields of sub-wavelength focusing, sub-diffraction focusing and super-resolution imaging. In order to enrich and expand the application of its focusing characteristics, a 1D PQC plano-V lens is proposed and the effect of material thickness on its focusing characteristics is studied in this paper. The results show that the lens can achieve sub-wavelength focusing and sub-diffraction focusing in a wide wavelength range of the second band. The results in this paper will provide reference for the design and application of 1D PQC plano-V lens.