Authorities said the 21-year-old student is alleged to have went on a stabbing spree in the eastern Chinese city of Wuxi.
Eight people have died after a stabbing attack at a Chinese school, with 17 others injured.
Authorities said in a statement that a 21-year-old student is believed to have carried out the attack in Yixing City, in China’s Jiangsu province.
The incident took place at the Wuxi Vocational College of Arts and Technology at around 6.30pm (10.30am in the UK) on Saturday, the Yixing police said.
Police said the suspect – identified only by his family name of Xu – graduated from the school earlier this year and was angry over not receiving his graduation certificate.
The Yixing Public Security Bureau added the student – who was also said to be unhappy with his internship pay – was apprehended and confessed to the crime.
It added that efforts were underway to treat the injured and investigate the case.
The incident comes days after 35 people were killed in the Chinese city of Zhuhai, when a motorist deliberately drove a car into people exercising at a sports centre.
Officers said a “number of” pedestrians were knocked down in the incident which took place on the eve of a biennial People’s Liberation Army exhibition in the southern Chinese city.
A 62-year-old man, identified only by his family name of Fan, was detained at the centre on Monday.
Police said he was apprehended in the car, which was described as being a small off-road vehicle, as he tried to flee the scene.