Abstract: The hot air anti-icing system is one of the important ways to prevent aircraft icing. Numerical simulation method was carried out to study the influence of the structural parameters on the thermal performance of the hot air anti-icing system. The hot air flow and heat transfer in the anti-icing cavities with different nozzle to surface height, number of the nozzle rows and hot air jet angle were simulated using the computational fluid dynamics (CFD) method. The thermal efficiency of the anti-icing system and the convective heat transfer coefficient distribution of the skin inner surface were obtained. The results show that: 1) with the increase of the nozzle-to-surface height in the range of 4mm to 36mm, the thermal efficiency of the anti-icing system reduces and the heat transfer performance of the hot air impinging on the surface weakens, 2) with consistent flow flux, the thermal efficiency of the anti-icing system increases from three to two nozzle rows, 3) the thermal efficiency improves with the 15° rotation of the hot air jet angle along the upper surface direction, indicating that the surface curvature effects the jet surface heat transfer performance. The results presented in this paper can help to the design of the anti-icing cavity.