China's supermarket sector was worth $970 billion at the end of 2011, surpassing the US market, which was valued at $913.5 billion, according to food industry analysts IGD.
The rapid expansion is being driven by China's growing economy, the rising wealth of its population, and inflationary food prices, the British firm said.
China's grocery market is forecast to expand to nearly $1.46 trillion by the end of 2014, three times its worth in 2006.
The report noted that the Chinese are moving from a diet based on rice and pork to embrace dairy products, wheat, grains, and both red and white meat, which has helped boost prices around the world.
The nation's growing appetite will also widen the gap with the US, which is forecast to expand to $1.07 trillion by the end of 2014.
The spending figures refer to outlays at supermarkets and open air markets, as well as bakeries and other specialized retail food sellers, IGD said.
The figures also include non-food products such as health, pet care, and home improvement-related items sold through supermarkets. The report takes into account China's slowing economy, which is forecast to cool to a growth rate of around 7.5% in 2012.
"Despite the slowdown, measures to stimulate Chinese domestic consumption present an opportunity for retailers. For example, higher wages could boost disposable income and increase the number of potential customers," Cécile Riverain, IGD's international research manager, was quoted by CNBC.com as saying.
The report also predicted that four BRIC countries - Brazil, Russia, India and China - will make up four of the top five grocery markets by 2015.'