The mainland is set to become the biggest contributor to world economic growth this year, replacing the United States as the chief engine of the global economy.
'The mainland will probably be the biggest contributor to global economic growth, even in terms of nominal exchange rates, as the US economy slumps,' said David Wyss, chief global economist at Standard & Poor's.
In purchasing power parity (PPP) - which values a currency in terms of its local buying power rather than according to the official exchange rate - the mainland was already well ahead of the US, he said.
Standard & Poor's estimates that the mainland will account for 33 per cent of the increase in global gross domestic product this year on a PPP basis compared to the US's share of 9 per cent. India will also overtake the US with a 12 per cent share.
Economists use PPP to give a more accurate reflection of a country's economic value. The measure avoids the problem of measuring the true value of the yuan which many economists say is significantly undervalued.
In conventional terms, the US was likely to recover from a two-year slump to account for 15 per cent of world growth by 2009, compared with the mainland's 12 per cent, Mr Wyss said.
'In PPP terms, China will continue to be No1. But in terms of the actual exchange rate it will probably be 10 years before China overtakes the US,' he said.