Abstract: A robust superdirective beamforming method for cylindrical arrays based on subarray processing is proposed. First, a signal model of two-level subarrays of a cylindrical array for beamforming is established, and then the optimal solutions of superdirectivity based on the eigenbeam decomposition and synthesis model are derived by using the circulant property of the noise cross-spectral matrix in the isotropic noise field. Compared to the traditional processing of the cylindrical arrays, the simulations of the sensitivity function, array gain and beampatterns of the proposed method are given. The resnlts show that the proposed method can obtain robust superdirective beampatterns and reduce the data storage and the amount of calculation. The achieved array gain in the low frequency band is much larger than that of the conventional beamforming. The proposed method provides another choice of the scheme for the actual underwater sonar array design.