Therefore, in this paper, iron ore plays the role of "independent variable" in the upward stage of price, that is, the increase of iron ore price causes the expectation of rising cost, which drives the spot and futures of thread to rise; In the downward stage of price, it plays the role of "dependent variable", that is, the decline of thread spot and futures caused by weak demand stimulates the market's expectation of reduced iron ore consumption and drives the spot price of iron ore to fall.

Iron ore is the main raw material for steel production, and the consumption of iron ore per ton of pig iron is about 1.5-2 tons. Considering the cost of steelmaking and steel rolling, the price relationship between iron ore and steel is.

In addition, the current iron ore port inventory is at a high level in recent years, not a low level.