By comparing the five major domestic steel mills four major raw material inventory changes, can be found in 2016, four kinds of raw materials inventory available days are less than the past four years. Among them, the coal industry and Q345B erw pipe production capacity to the rhythm are different, injection of coal and coking coal inventory levels fell more significantly than in previous years. 2016 steel mills generally adapt to the state of low inventory of raw materials, raw material inventories increased in April is due to the current real estate market than expected warmer, but in May the real estate market indicators fell, the steel did not change the whole Year economic expected cold tone, maintaining a low inventory of raw materials line.