声发射检测技术作为一种新兴的无损检测技术，越来越多地应用于常压储罐的罐底板腐蚀检测，自标定作为检测前确定声速的重要步骤，严重影响到声发射检测的定位准确度。介绍了声发射检测自标定的基本原理和重要作用，应用德国VALLEN AMSY-5声发射仪，通过现场试验确定了影响常压储罐罐底板声发射检测自标定准确的主要因素，并针对各因素提出了改善方法，为提高自标定的成功率，保证声发射检测的准确性提供了可靠保障。

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.