Uber is losing $1 billion a year in China as it faces "fierce competition" from rival Didi Kuadi.
The private car hire app's CEO Travis Kalanick said it was not yet profitable in mainland China because of intense competition as its rival buys up market share.
Uber's valuation of its Chinese business soared last month to $8 billion.
According to Canadian tech news site Betakit, Kalanick said: "We're profitable in the USA, but we're losing over $1bn a year in China.
"We have a fierce competitor that's unprofitable in every city they exist in, but they're buying up market share. I wish the world wasn't that way."
Rival Didi Kuadi is backed by Chinese technology giants Tencent and Alibaba and recently partnered with Uber's rival Lyft.
A spokesperson for Didi Kuadi rejected Kalanick's claims saying it was benefiting from its larger size.
"Smaller competitors have to bleed subsidies to make up for their insufficient driver and rider network."
He added that the Chinese company now operates in 400 cities and is performing well in more than half of those cities.