Mini is finding its feet in China after a slow start following its introduction in 2005. Back then it recorded just 430 sales but last year it hit a record 15,500.
The British brand is still growing, up 33% to 7,000 units year on year in the first four months of this year.
Friedrich Eichiner, finance chief of parent BMW, said: "We originally launched Mini with a high price point as part of a niche premium strategy so sales were slow to begin with. We adjusted this strategy last year and sales have really taken off.
"We still market the cars as premium models and they are seen in China as chic and fashionable."
Meanwhile, BMW's other British brand, Rolls-Royce, has also seen China catch up with the US as its biggest market in the world. Although, country by country figures have not been broken down, sales of the UK's famous luxury limo were up 6.5% globally in the first three months of this year to 770.
Both brands are part of a wider BMW Group success story in China where the group has sold 107,000 vehicles in the first four months, up 35%. Its total sales last year reached a record 233,000.
Eichiner was in China along with BMW chairman Norbert Reithofer for the opening this week of the company's second plant in Shenyang in the north eastern part of the country, a joint venture with local partner Brilliance Automotive.
The factory will build the X1 small SUV and the new long-wheelbase 3 series, a model specifically designed for the Chinese market. The new Tiexi plant will double BMW's capacity in Shenyang to 200,000 vehicles a year although Eichiner said the plan is to increase this to 300,000 by the end of next year.
Reithofer was even more bullish, saying that due to the flexible production structure, up to 400,000 will be possible.