Expert system is a very important application domain of artificial intelligence technology. In this paper, expert system was firstly applied in beer spoilage microorganism control for artificial intelligence domain. By using basic elements of expert system, knowledge about beer, spoilage microorganisms and experiment technique were organized and processed in the expert system. Beer-spoilage Microorganism Control Expert System(BSMCES) was designed and developed on the platform of Apache, PHP and MySQL. This system has several significant functions, including information consultation, control contamination, decision-making and technology service.