Abstract: To verify the method proposed in the paper “A new method of broadband constant beamwidth beamforming for arbitrary geometry arrays”(ACTA ACOUSTICA (In Chinese), 2001; 26 (1): 55-58), lake-experiment was carried out for a 24-element uniform circular array. Based on the data collected from the experiment, constant beamwidth beams were formed at eight different frequencies covered one-octave frequency band. The big difference between measured and theoretic manifold of the circular array showed that the broadband constant beamwidth beamforming method used in the paper has good tolerance.