China gets most of it's iron ore through mines in China.
China produced most of it's Iron ore from it's own Iron ore mines in China between March 2015 and March 2016, a total of 1,459.5 million tons of Iron Ore was mined in those China Iron Ore Mines.
China also has some Iron Ore shipped in from places such as Australia, Brazil, India, and South Africa.
China also produces new Iron through use of scrap Iron and Scrap Tin that they have bought and have had imported from the USA and other countries.
If you've ever sold any scrap metal such as scrap iron and scrap tin to a scrap yard then eventually that scrap was likely sent over to China on a scrap metal ship.
But China does still produce it's Iron Ore as of now and likely will continue to do so until they deplete the Iron Ore.
There are lots more Iron Ore in many other places as well.