The 40-year-old man, only identified by the surname Yu, was taken into custody late Monday after he allegedly attacked the kids at an elementary school in Chaoyangpo village of Enshi city in Hubei province.
It was not immediately clear how the children were attacked.
The man was released from Hubei prison last June after serving a sentence for attempted murder, according to local media. A possible motive was not immediately clear either.
The attack is the latest in a string of similar incidents in China.
In January, 20 children were injured after a man attacked them inside an elementary school in Beijing — and in June 2018, two children were stabbed to death by a man outside an elementary school in Shanghai.
In April of last year, nine were killed and more than a dozen injured outside a middle school in northwestern Shaanxi province by an attacker who allegedly was a former pupil seeking revenge for having been bullied.
The Associated Press contributed to this report.