Blast furnace (BF) still maintains its dominant role as a major iron-producing route but often suffers from the operational instabilities resulting from the 3D asymmetric distributions. This problem has never been seriously addressed due to the complexity of BF and the lack of effective measuring techniques. In this thesis, a comprehensive 3D BF process model has been developed. A series of BF key features are explicitly considered, aiming to give much more realistic predictions of BF inner states and the global performance indicators. Based on this 3D model, the 3D asymmetric BF inner states are firstly investigated.