The girl's father denies abusing his daughter by forcing her to run
Zhang Huimin, eight, rose each day at 0230 and ran about 1.5 marathons (64km, 40 miles), Xinhua news agency said. Her father accompanied her on a bicycle.
He said the feat was aimed at drawing attention to her Olympic potential ahead of the Beijing games next year.
He denied forcing her to run, but some experts have said it amounted to abuse.
The girl arrived in the Chinese capital on Sunday after starting out in Hainan on 3 July.
Zhang Huimin, who is 1.22m (4ft) tall and weighs 21kg (46lb), is too young to compete in the 2008 Olympics but her father, Zhang Jianmin, believes she can compete in the 2016 games, when she will be 17.
Domestic media and some experts have accused her father of abuse, saying running such long distances could damage the girl's body and affect her growth.
"I make the training fun for her. I don't push her," Mr Zhang told the Beijing News.
"She loves to run. Many people don't understand us," he said.
Zhang and his wife have separated, mainly because she opposed his way of training their daughter, the newspaper reported."Whether people oppose it or not, we will soldier on," Mr Zhang said.