The previous February a knife-wielding assailant wounded 10 children in Haikou, in the southern island province of Hainan, before committing suicide.
The man had entered the school in the afternoon, claiming that he was there to pick up his son.
The attacks have led to calls for more research into the root causes of such acts.
Violent crime has been on the rise in China in recent decades as the nation’s economy has boomed and the gap between rich and poor has widened rapidly.
Studies have also described a rise in the prevalence of mental disorders, some of them linked to stress as the pace of life becomes faster and support systems wither.
In June last year, a bomb blast that killed eight people and injured dozens outside a kindergarten in Fengxian, eastern China, was blamed on a 22-year-old introvert with health problems who had written the words “death” and “destroy” on the walls of his apartment. Material to make a homemade explosive device was found in the home.