Abstract: The variation characteristics of bubble morphology and the thermal-physical properties of bubble boundary in the top-blown smelting furnace were explored by means of the computational fluid dynamics method. The essential aspects of the fluid phase (e.g., splashing volume, dead zone of copper slag, and gas penetration depth) were explored together with the effect of sinusoidal pulsating gas intake on the momentum-transfer performance between phases. The results illustrated that two relatively larger vortices and two smaller vortices appear in the bubble waist and below the lance, respectively. The expansion of larger ones as well as the shrinking of smaller ones combine to cause the contraction of the bubble waist. Compared to the results of the case with a fixed gas injection velocity (V_g = 58 m/s), the splashing volume and dead zone volume of the slag under the V_g = 58 + 10sin(2πt) condition are reduced by 24.9% and 23.5%, respectively, where t represents the instant time. Gas penetration depth and slag motion velocity of the latter are 1.03 and 1.31 times higher than those of the former, respectively.