We report an outbreak of food poisoning that occurred in August 2008 in a group of 13 persons who ate Stewed Pork Balls in Brown Sauce in Beijing. Epidemiology investigation and case-control analysis indicated that the Stewed Pork Balls in Brown Sauce was the source of food poisoning (OR 3.34, 95% CI 1.30–8.65). With the different measurements including API 20E and PCR, Dienes typing and PFGE, Proteus mirabilis was identified as a contributor to this matter, which evaluated by analyzing the collectives, which derived from contaminated food, patients, cook handlers and waiter. So this is the first report that P. mirabilis as a culprit resulted in food poisoning in Beijing.