At $14.5bn (£9.2bn), the surplus stands at less than half the $31.5bn seen in July and is down from $17.8bn in August.
Trade did grow, with exports up by 17.1 per cent over the year, and imports grew by 20.9 per cent, but it was slower than in earlier months.
The slowdown in EU demand was particularly stark, with growth standing at 9.8 per cent, year-on-year, down from 22 per cent in August.
“China’s only real growth engine – exports – has sputtered,” said Lombard Street Research’s Diana Choyleva. “GDP growth has slowed down fast.”