China’s imports in August fell 14.3% in yuan-denominated terms from a year ago, while exports fell by 6.1%.
The steep fall in the value of imports reflects lower commodity prices globally, particularly crude oil.
The numbers mean China’s monthly trade surplus expanded by close to 40% from the month earlier to 368bn yuan ($57.8bn; £37.7bn).
China recently revised down its 2014 economic growth from 7.4% to 7.3%, its weakest for almost 25 years.
In US dollar denominated terms, exports for the month of August fell 5.5% from a year earlier – slightly less than expected – while imports fell by 13.8%, leaving China with a surplus of $60.24bn.
Currency conversion factors based on US dollar and Chinese yuan movements over the last year mean some official numbers from the mainland are now reported in both currencies.