Abstract: In order to find congenital defects in new pressure vessels in time and improve containers manufacturing quality, a new hydrogenation reactor during water pressure experiment with acoustic emission technique was tested. Using triangulation and line positioning method, the hydrogenation reactors shell and pipe was detected in whole. Focus was put on monitoring acoustic emission source localization signal in the second loading cycle and packing phase. During the testing process 3 effective acoustic sources in total was discovered. Through using ultrasonic test and liquid penetrant test in foundation of acoustic emission testing, result was assurance as follows: acoustic sources S1 was the flow noise, acoustic sources S2 was the mechanical friction signal between saddle and cylinder while loading, acoustic sources S3 was surface defects in bent pipes layer. This instant testing could offer a reference to new manufacturing pressure vessels before leaving the factory.