Atmospheric storage tanks are mainly used to store hazardous chemicals. Once leakage occurs, it will cause catastrophic accidents such as explosion, fire or poisoning, resulting in significant loss of life and property, environmental pollution and adverse social impact. Floor leakage is the main failure mode of atmospheric storage tank, so it is very important to monitor whether there is leakage of tank floor by appropriate methods. Acoustic emission (AE) technology has been widely used in predicting the location of leakage points of tank floor. However, there are few reports on the application of AE technology in dynamic monitoring of leakage or not of the tank floor. In this paper, a suspected leaking tank is taken as the research object to carry out acoustic emission monitoring under different liquid level conditions. The feature extraction and parameter analysis of the monitoring signal are carried out, and the leakage signal is identified by comparison with the typical leakage signal. The results show that there is no leakage signal during the monitoring period and no leakage occurs on the bottom plate of the tank. Practice has proved that the tank is still in good operation. The application of acoustic emission technology to monitor whether the floor leaks or not solves the passive situation that enterprises cannot stop production and repair due to the shortage of tank capacity, and avoids the economic losses caused by blindly opening tanks, on the other hand, it can push acoustic emission technology to a new application field.