Qu is the girlfriend of Vancouver mayor Gregor Robertson.
On Friday, Wanting Qu posted a message on her Facebook page, expressing her sadness.
"I love my mom dearly and I am truly heartbroken," the post states. "This ordeal is very stressful and I find myself ... crying over it daily.
"I appreciate the love and support from my friends, my fans and my family. I will use your strength to get through these tough times."
China Daily reports that her mother, Qu Zhang Mingjie, a Harbin city official, was arrested after allegedly undervaluing state assets for sale, and is currently being held in detention.
According to South China Morning Post, Zhang Mingjie was dismissed from her position as deputy director of Harbin's development and reform commission in September 2014.
Wanting Qu's relationship with Vancouver mayor Gregor Robertson made headlines earlier this year. Robertson had announced his spilt from his wife Amy, last summer.
Robertson has attributed his following on Chinese micro-blogging site Weibo, in part, to Wu, who has hundreds of thousands of followers on the site.
The mayor is expected to be asked for comment later Friday after a council meeting.