Mr Yin's mother quit her job to conduct her search for him across 10 provinces in China. In 2007, Mrs Li started volunteering with a group called "Baby Come Back Home", to help other parents look for their missing children.
According to state media, she helped reunite 29 children with their families, while her own son was still missing. She intends to keep working with the group.
Police say that after his abduction, Mr Yin was sold to a childless couple for 6,000 yuan, equivalent to £640 today. He was found living in Sichuan province, which is approximately 620 miles from Xian, where he now runs a home decoration business.
Police have not released any further information on the people who raised Mr Yin and his abduction remains under active investigation.
The practice of child trafficking for illegal adoption is not uncommon in China and has a long history. In 2015, it was estimated that 20,000 children were trafficked within the country.
While there are no official figures on the number of abductions over the decades, the Baby Come Back Home website alone has 14,893 posts looking for missing boys, and 7,411 looking for girls.
A Chinese man who was abducted aged 2 from a hotel in 1988 has finally been reunited with his parents after 32 years.
Mao Yin was abducted as he and his father walked home from nursery in the city of Xian in Shaanxi province. The boy had asked for a drink of water, so they stopped at the entrance to a hotel, but as his father cooled some hot water to drink, the youngster was taken.
His parents searched across China for him and his mother distributed 100,000 flyers in an attempt to find him, before they were finally reunited at a police news conference on Monday.
"I would like to thank the tens of thousands of people who helped us," said Li Jingzhi, the boy's mother. Mr Yin, who has since been renamed Gu Ningning said he was "not sure" about the future, but in the short term would spend time with his parents.
Last month, the Chinese police were given a tip off that a man had brought a child from Shaanxi to Sichuan province in the late 1980s.
Police created a mocked up image of what they expected Mr Yin to look like, using a photograph of him as a child and facial recognition software. They then compared the simulated image with photos in the national database. A potential match was found and a DNA test was ordered. The test results were returned on May 10, which is Mother’s Day in China.