Nearly 15.4 million barrels of Shanghai's most-active September contract changed hands in the 2-1/2-hour morning session to 03.30 GMT.
"President Donald Trump continues to suggest the USA will pull out from (the) Iran nuclear deal, which raises the spectre of bringing back sanctions on the country and severely limiting Tehran's ability to export crude oil", said Stephen Innes, head of trading for Asia/Pacific at futures brokerage OANDA in Singapore.
The exchange said that foreign companies, including Glencore PLC and Trafigura Group, participated in the debut via brokers.
A resurgence in risk appetite has helped lift markets from equities to commodities after a report that the Trump administration is urging China to lower tariffs on cars during talks to calm trade tensions.
Wood Mackenzie's research director Sushant Gupta, commented "China surpassed the U.S. to become the world's largest importer of crude in 2017". However, some analysts expressed doubts over the petro-yuan's success, citing the fact that China is still not recognized as a market economy and the country's authorities may interfere with trading at the first signs of a potential bubble.
CRUDE oil futures slipped on Monday as investors cashed in some profits from last week's rally but concerns about Saudi-Iran tensions kept losses in check. Still, concerns over American shale oil remain, with analysts forecasting a gain in USA crude inventories last week.
It's taken a quarter of a century, but China finally has its own oil futures.
Mozilla suspends ads on Facebook on data privacy concerns
You may have heard about a quiz app built by a university researched that leaked Facebook data of millions of people in 2014. Zuckerberg said this week he would be willing to testify if he is the right person at the company to speak to lawmakers.
At 9:24 a.m. (0224 GMT) prices were up 3.29 per cent at 430 yuan, with 19,122 lots, equal to 19.1 million barrels of oil, traded.
Hong Kong-based Unipec Asia will buy the crude delivered to China for one year starting from September, said the source who declined to be named.
Analysts said the market's current strength may not last.
However, a production-cutting pact between the OPEC, Russia and other producers has given a strong tailwind to oil prices, with both benchmarks hitting levels not seen since December 2014.
These and other factors mean the contract may have a "hard time" building correlations with Brent and WTI that would make arbitrage possible, said Albert Helmig, chief executive of financial consultancy Grey House and a former vice chairman of NYMEX.
This could be seen as competition to the Dubai Mercantile Exchange's (DME) crude futures and potentially the assessments published by price reporting agency S&P Global Platts.