Sun, the 5,000m bronze medallist at the 2003 World Championships who is currently serving a two-year ban for doping, said coach Wang Dexian subjected her to frequent beatings.
“My back is covered with so many cuts and bruises that I cannot even take off my clothes,” she said in a TV interview.
The alleged abuse came to a head recently when she was whipped with a belt after a difference of opinion with Wang’s wife, Zhu Fengling.
“He beat me with a belt after I contradicted his wife. It was the most ruthless (attack) since I started training with him 10 years ago,” Sun, 27, said.
Sun is now training alone in a bid to make a comeback for the 2008 Olympics in Beijing.
The runner failed a dope test at the National Games in October last year, and was banned from international sport until October 19, 2007.
However, in December last year Sun won a court case against fellow athlete Yu Haijiang, whom she accused of spiking her drinks, causing her to fail the test. But the sprinter was stripped of her 10,000m title at the National Games and thrown out of the tournament, which was seen as a dress rehearsal for the 2008 Olympics.