Two batches of fake mutton were found and banned from Beijing's markets, Beijing Times reported.
Duck and pork were found in sliced "mutton" during an inspection by the Beijing Administration for Industry and Commerce, after mutton-related scandals were reported earlier this year.
Fake mutton is hard to identify and usually used by barbecue stalls and small hotpot restaurants, the paper said.
China has long been plagued by food safety issues, and many of the recent scares have involved its meat trade.
This year, authorities seized 20,000 tons of illegal products and solved 382 cases of meat-related crime – primarily the sale of toxic, diseased and fake meat, during a three-month campaign. More than 900 people have been arrested, including a gang that made more than $1.6 million by passing off fox, mink and rat meat as mutton, the country's public security ministry announced.