Abstract: Shift converter is one of the key equipment in synthetic ammonia plant. Safe operation of the converter is important to the whole device. This paper introduces the real-time monitoring of the converter without shutting down by applying acoustic emission technology which can provide important guarantee for the safe operation of the converter. There are few researches on the long-term real-time monitoring of this kind of equipment using acoustic emission technology in China. Through analysis on the acoustic emission monitoring for four months, it is found that this technology is highly effective in identifying the crack in the converter pipe and its surrounding area; and with the monitoring time increasing, the amplitude of the acoustic emission signal is gradually increasing.