The little girl, identified as Wang Yue, was wandering through the alley outside her father's hardware store in the city of Foshan when a white truck hit the girl, and then a second vehicle also ran over her.
A dozen people walked by before a Good Samaritan finally helped the child, who was lying in a pool of blood.
She remains in critical condition at the Guangzhou Military District General Hospital. The Guangzhou Daily quoted the hospital's head of neurosurgery as saying the girl is likely to remain in a vegetative state if she survives.
Chinese police say the two drivers were arrested.
The case is the latest heavily publicized example of Chinese in distress being ignored by fellow citizens in a phenomenon seen as illustrating the corrosive effect China's headlong pursuit of economic growth has had on public ethics.
"This brings a blow to our morality," news reader Yan Yanzi from Southern Television Guangdong said in a report that has been uploaded to video-sharing sites. "Where was your conscience? It is really disappointing news to watch, really disappointing," she said at the end of the report.
The TV report has been viewed more than 2 million times on the Internet television site of Youku.com Inc. China's version of Twitter, Sina Corp.'s Sina Weibo, has drawn 4.4 million comments and organized them under the hash tag "Please end the cold-heartedness."
The Associated Press contributed to this report.