Abstract: Because of the signal information error of direction,the robustness of the broadband focusing transform beamforming methods deteriorates.To overcome the shortcoming,a rolmst broadband beam forming method based on the focusing transform approach was presented.To achieve a constant beamwidth for acoustic detection,the proposed method mainly applies the idea of second-order cone programming.The beam forming methods can get more exact weights and then reduce the focused data error.Thus it can improve the robustness performance of the focused beamformer.The beam forming on the circular sensor array is optimized by the computer and demonstrated in the experiment.The experimental results show that the method has a good tolerance to the signal message error and we can achieve a constant beam width beam pattern.So it can be applied to real sonar detection.And it has higher robustness than the traditional second-order cone method of constant,beam width.