Abstract: Jacketed structure equipment is common in chemical industry, all kinds of problems such as corrosion will cause its damage and particularly cause the leakage of the inner shell, resulting possibly very serious consequence. As a kind of dynamic detection method, acoustic emission testing technology can detect mechanical wave and test the equipment at real-time, so with this technology, one can monitor the leakage of the jacketed equipment and can also find leakage location in time and determine the severity preliminarily. In this paper, for the leakage of jacketed equipment, we will study the changing relationship between acoustic emission signal and leakage pressure and the difference of the changes in amplitude between single-hole leakage and porous leakage when the jacketed media is gas and the inner pipe has leakage problem, thus laying the foundation for industrial application.