Abstract: The directivity test of the transducer is one of the basic acoustic performance test items. In this paper, the deviation between the sound center and the rotation center of the mechanical device is calculated in transducer directivity test, which shows that the deviation will directly introduce the amplitude and angle deviations of the test result to change the directivity pattern of a full-directional transducer into a pattern similar to heart-shape; and then a correction method for directivity pattern is proposed. The actual test results show that the correction method proposed in this paper is effective when the deviation between the mechanical rotation center and the sound center exists; and as the rotation radius of the mechanical device increases, the correction effect is gradually getting better. This method helps to improve the accuracy of the directivity measurement of underwater acoustic transducer, and has good engineering applicability.