At gang of least five men armed with knives burst into the dormitory of a vocational college today and slashed nine students, one of them seriously.
Four students had been wounded in an earlier confrontation between the two groups, bringing the total injured to 13.
The attack has sparked new fears in a country on edge over a series of shocking rampages, many of them at schools.
The pre-dawn attack took place in Haikou, the capital of the southern island province of Hainan, when the gang burst into the Hainan Institute of Science and Technology and slashed the students, the China News Service reported.
The official Xinhua News Agency said the gang first assaulted a guard and disabled security cameras before rushing into two dormitories where lights remained on and hacking away apparently at random.
The China News Service said eight students were wounded slightly, while one's hand was cut off. Two students remained in hospital with wounds that were not life-threatening, the reports said.
The students, who were in their late teens and early 20s, were much older than the children targeted in a string of attacks at schools across China in the last two months.
The reports said the violence began with a confrontation last night between some of the college's students eating at a food stall outside the school and men from the surrounding villages.
Four of the students were attacked with knives and police were called, but left after questioning the students, the reports said. The villagers then called for reinforcements and attacked the school several hours later.
The attack follows five separate assaults by lone assailants against schoolchildren as young as three in the last two months that have left 17 dead and more than 50 wounded, including some adults.
The violence has resulted in a boost of security at schools across China, with nervous parents accompanying students to school and police and security guards posted at entrances.
While revenge was the apparent motive in the latest attack, previous rampages have involved apparently deranged people seeking to vent their rage on innocent victims with whom they had little or no connection.
Sociologists say those attacks reflect a failure to diagnose and treat mental illness, along with anger and frustration among people who feel victimised by China's high-stress, fast-changing society. Experts say the frequency of the attacks and choice of schoolchildren as the main victims suggest a copycat element.
AP