Chen Zhengping was sentenced after a trial in the Nanjing Intermediate People’s Court.
The poisonings on September 15 also made up to 300 people ill.
The website Chinanews.com reported that, as Chen was taken to court amid heavy security, residents lined the road to watch and praised authorities for acting swiftly. More than 20 police vehicles formed a convoy to escort Chen to court.
Chen was arrested on September 16 aboard a train in Zhengzhou, a city about 370 miles northwest of Nanjing.
Chen, the owner of a rival snack shop, confessed a day later to spreading rat poison, according to the official Xinhua News Agency.
He said he was resentful over his rival’s success.
Authorities have tightly controlled information about the poisonings and did not release a death toll for four days.
Tests on the Nanjing food identified the substance as a brand of rat poison called Dushuqiang, which has been banned for sale in China since the mid-1990s.