Very often, there are several kinds of different scale structures, such as atomic/molecular microscale, device/boundary mesoscale and working procedure/operation unit macroscale, etc., referred in the operation of a blast furnace system. However, not enough attention has been paid to the multiscale feature of the blast furnace system by traditional analytic methods which are the average ones over a fixed scale. For this reason, the current work performs a multiscale identification and further makes a dynamical analysis on the blast furnace system from the time series sets of two important components in the blast furnace hot metal, i.e., silicon content and sulfur content, collected from a pint-sized blast furnace. The results render a strong indication of multiscale characteristic and multiple dynamics, i.e., randomicity, chaos, and limit cycle but with different rates of contribution to the whole system, contained in the blast furnace system. Furthermore, compared with the original blast furnace system, every subscale structure has lower complexity. All of these can serve as guidelines to carry out modeling, control and optimization on complex blast furnace system from the viewpoint of multiscale in the future, and may throw more light on understanding and characterizing its complex dynamics. (C) 2011 American Institute of Chemical Engineers AIChE J, 57: 3448-3458, 2011