The group was sentenced to between two and 15 years in prison and slapped with fines, the Beijing Second Intermediate People's Court said on its official account on China's Twitter-like Weibo.
Questions of how to deal with Taiwanese arrested abroad have become a sensitive diplomatic issue, with Taipei protesting that suspects should be returned to the self-ruled island, rather than the mainland.
China and Taiwan split after a civil war in 1949 and Taiwan sees itself as a sovereign nation, but Beijing considers it a breakaway province that is part of its territory -- a stance that most countries around the world recognise.
Taipei has in the past accused Beijing of "abducting" Taiwanese suspected of committing fraud abroad and taking them to China.
Ties between Beijing and Taiwan have worsened since President Tsai Ing-wen of the Beijing-sceptic DPP took office last year, as she has refused to acknowledge the island is part of "one China".
The incident is the latest of several international deportations of Taiwanese suspects recently, and analysts see the cases as a Chinese bid to pile pressure on the Taiwanese leader.
A Spanish court said last week it had also decided to allow the extradition of Taiwanese fraud suspects to China despite protests by Taipei, which hoped to take back its citizens.