Abstract: In this paper, the frequency bandwidth characteristics analysis method of the narrow wall slotted-waveguide array is presented. In nonresonant waveguide-fed slot-antenna arrays, the slots conductance is variational in frequency bandwidth, and it will change the aperture distributions and affect the beam performances. By calculating the beam performances corresponding different slots distributions, the selections of the main design parameters are discussed. An experiment antenna is made and results are consistent with the theoretical analysis.