Abstract: As a new nondestructive testing technology, acoustic emission detection technology was more and more used for atmospheric storage tanks of the tank bottom plate corrosion detection, and the self-calibration was an important step as a pre-test to determine the speed of sound, which seriously affected the accurate positioning of acoustic emission testing degrees. This paper introduced the basic principles and the important role of the self-calibration of acoustic emission testing and used the VALLEN AMSY-5 system in field test to determine the main factors affecting the accuracy of self-calibration of atmospheric storage tank floor acoustic emission testing. Various measures were proposed to improve the success rate of self-calibration in order to ensure the accuracy and reliability of acoustic emission testing.