To study the influence of beam weighting on array directivity in the development of multi-beam fishing sonar. Based on the horizontal omnidirectional scanning fishing sonar, cylindrical sonar array is equivalent to a plurality of vertically arranged circular arc arrays in this paper. Matlab programming software is used to simulate the linear and nonlinear weighting method. The effects of similarity weighting method and minimum power weighting in the inhibition region method on the directivity of cylindrical arrays are compared. Combined with the existing test conditions, beam directivity of two nonlinear weighting methods are tested in the anechoic sonar test pool.The simulation and test results show that the two nonlinear weighting methods are more suitable for horizontal omnidirectional scanning multi-beam fishing sonar. The similar weighting method has a better effect on improving the beam directivity of the cylindrical array transducer,the main lobe width increases only about 1°, and the side lobes reduces about 9 dB compared with the unweighted beam side lobes.The research shows that the similar weighting method can be selected in the cylindrical array transducer to improve the directivity of the array.