From establishing corrosion mechanism and hearth heat transmission system to hearth design theory， this paper analyzed the key factors of structure design， and made a full-scale dissertation of the long life of blast furnace hearth. The key factors of long campaign life of blast furnace are: design， construction， furnace drying， start up， stable operation and maintenance. With proper cooling system and structural configuration， the most important issue for blast furnace hearth long life would be avoiding gas gap. To avoid gas gap in blast furnace hearth， measures should be taken in design and every step should be controlled strictly during hearth installation. It is also helpful to use hot water for furnace drying for avoiding gas gap， because higher side wall refractory temperature can accelerate water evaporation. To achieve a non-gas gap operation， the furnace starting process should also be carefully con- trolled to give the new blast furnace a period to form a effective and reliable heat transmission system. For any kind of refractory structure and cooling system， appropriate heat transmission system is necessary for blast furnace hearth to form steady slag skull， and consequently achieve a long life.