The Supreme People's Court has overturned the death sentences handed to two men convicted of raping and forcing an 11-year-old girl to work in a brothel.
The court said the high-profile case, which has received national media attention, would be retried.
Tang Hui, the victim's mother, has campaigned for years believing death sentences should be handed out to all people who were guilty in her daughter's case.
She has also petitioned local governments to punish officials who she said had been bribed by prostitution gangs to protect their operations.
"The ruling has dealt a heavy blow to us," Tang told the South China Morning Post yesterday.
"My family just tries to live a normal life. As the case reopens, we'll experience all the nightmares again. I'm especially worried about my daughter."
Tang's daughter has contracted herpes, an incurable sexually transmitted disease, and psychological trauma after she was raped and forced to work as a prostitute at the age 11 for two months in a brothel in Yongzhou in Hunan province in 2006.
Her daughter's two main kidnappers were sentenced to death in June 2012, four accomplices received life sentences and one was jailed for 15 years.
A representative from the Supreme People's Court said in an interview with the People's Daily that the death sentences had been overturned because the crimes were not serious enough to warrant capital punishment.
"The circumstances of the crime had not reached the degree of being extremely serious," the spokesman said.
Forcing a large number of victims into prostitution, or performing torture on victims that resulted in death or permanent injury might have warranted the death sentence, the official added.
Lu Miaoqing , a lawyer in Guangzhou, said the Supreme People's Court ruling was understandable as judges tended to avoid capital punishment unless a crime had caused deaths.
In August 2012, the local authorities sentenced Tang Hui to 18-months re-education through labour after she petition ed for the death sentence for all the people convicted in her daughter's case.
Her protests had "seriously disturbed the social order and exerted a negative impact on society", Xinhua reported.
Lawyers representing Tang publicised her story on microblogs and received nationwide attention and support. The local authority reversed its decision and released her after locking her up in the labour camp for nine days. "If [my daughter's] case opens and fails to deliver justice, I will appeal and petition again," she said.
Si Weijiang, the lawyer representing Tang, said they would collect new evidence and present the facts to the court. "I'm afraid that another two to three years might burn Tang out and the rest of her family. She may learn to accept the possibility that the criminals will not die," Si said.