The stabbing, in which another 17 people were injured, took place as the public was still mourning a deadly car attack in southern Zhuhai city days before.
At least 35 people were killed and 43 others injured on Monday as an SUV rammed into a crowd at a sports stadium, raising huge concerns over social stability and prompting Beijing to order more precautionary actions.
Saturday’s attack took place at around 6.30pm at the Wuxi Vocational Institute of Arts and Technology in Yixing, a city in Jiangsu province about 200km (120 miles) west of Shanghai.
The suspect, a 21-year-old surnamed Xu who used to study at the college, was detained at the scene, local police said.
The college has more than 10,000 students and employs 590 staff.