Abstract: An improved design of single-ridge waveguide slot arrays is proposed in this paper.First the structural dimensions of single-ridge waveguide be determined by analyzing the influence of the ridge dimensions on theadmittance of isolated slot in single-ridge waveguide ;Then the entire array is preliminary designed with the Elliott’s classicaltheory ；In order to eliminate the influence of mutual coupling 、edge diffraction and other factors on the sidelobe level, the offsetand length of each slot are adjusted according to the near-field on slot aperture. To verify the effectiveness of this method, aneight-element single ridge waveguide slot arrays is designed . Simulation results show that the antenna VSWR bandwidth is about9.5%（VSWR<1.5）, and sidelobe less than -25dB, so the performance has been greatly improved as compared with existingliteratures.