In November, the attacker, named as Huang Wen, repeatedly rammed his car into a crowd outside a primary school in Hunan province, state broadcaster CCTV said.

When the vehicle malfunctioned and stopped, Huang got out and attacked bystanders with a weapon before being apprehended.

30 people, including 18 pupils, sustained minor injuries.

The court found that Huang had sought to "vent his emotions" over financial losses from investments and conflicts with family members, CCTV said.

Huang's sentence may be converted to life imprisonment after two years, according to Chinese law.

Many Chinese social media users on Monday complained the sentence was too light.

"How is this possible? Shouldn't it be immediate execution?" asked one user on the Weibo platform.

"Don't release this person. I'm afraid," said another.

Footage circulating on Chinese social media the day of the crash appeared to show the aftermath of the incident, with dozens of children running in panic away from the site of the crash yelling "help, help".

Another showed a bloodied man being hit with sticks by passersby shouting "beat him!" as he lay on the ground next to an SUV.

China has this year seen a string of mass casualty incidents -- from stabbings to car attacks -- challenging its reputation for good public security.

Some analysts have linked the incidents to growing anger and desperation at the country's slowing economy and a sense that society is becoming more stratified.

In November a man killed 35 people and wounded more than 40 when he rammed his car into a crowd in the southern city of Zhuhai -- the country's deadliest attack in a decade.

And in the same month, eight people were killed and 17 wounded in a knife attack at a vocational school in the eastern Chinese city of Yixing.