Large-current switchgears are important basic components of power system. In order to reduce the temperature rise and energy consumption of the large-current switchgear, the thermal-fluid coupling model is established based on the thermal convection and radiation. Then, three structure factors (vertical spacing, deflection angle and inlet speed of three-phase busbars) are carried out through the response surface methodology (the average surface temperature of B-phase busbar as the response value). The results show that the thermal-fluid coupling model, which is put forward for Large-current switchgear in this paper, is more accurate than traditional engineering algorithm. The deflection angle has little effect on the average surface temperature of B-phase busbar, while vertical spacing and inlet speed have significant impact on the temperature rise and energy consumption of B-phase busbar. The recommended optimal switchgear structure is the vertical spacing of 200 mm, the deflection angle of 73.5 °, and the inlet wind speed of 2.24 m/s. Compared with the initial experimental model, the temperature rise is reduced by 5.1%, and the energy saving rate is increased by 5.89%. The research provides an important basis for predicting the temperature rise and structural optimization for large-current switchgear.