The man surnamed Fan is from Shaoyang City of central China's Hunan Province, state-run Xinhua news agency reported.
Local police said the assailant was arrested with help of people at the scene.
The victims have been admitted to Guangzhou Armed Police Hospital where they have been put under observation after being provided treatment.
Witness Luo Xianggui, whose husband is among the injured, said the assailant lived across the street and showed no oddness during daily contacts.
The attacker, whose motive remains unknown, was also hospitalised.
A number of such knife attacks were reported from different parts of China allegedly by either disgruntled or mentally disturbed people.
Among the most shocking was a May market attack in restive Xinjiang region in which 39 people were killed.
Another deadly rampage by knife-wielding assailants happened at a train station at Kunming in China's southwest in March, which left 29 dead.