Abstract: According to the common feature of four kinds of furnaces, including type A furnace with single flue but no slag partition wall, type B furnace with single flue and a slag partition wall, type C furnace with double flues but no slag partition wall and type D furnace with double flues and a slag partition wall, the copper flash continuous smelting furnace was considered as a synthesis reactor of two relatively independent processes: flash matte smelting process (FMSP) and copper continuous converting process (CCCP), and then the thermodynamic model of the copper flash continuous smelting process was developed by establishing the multi-phase equilibrium model of FMSP and the local-equilibrium model of CCCP and combining them through the smelting intermediate product. Based on the thermodynamic model, the influences of the furnace structures were investigated on the thermodynamic formation condition of blister copper, the Fe3O4 behavior, the copper content in slag and the recovery rate of copper. Results show that the type D furnace is an ideal reactor for copper flash continuous smelting, and hence, it's effective to keep the FMSP and the CCCP in relatively independent partitions and to make their gases discharge out of the furnace from respective flues.