Taking the super heat-resistant aviation gear steel 12Co14Ni6Cr5Mo4VNb cylindrical gear as the research object， the high-frequency pulse method was used to conduct bending fatigue performance tests on gears with different surface modifications. Through experimental data analysis and gear tooth failure mechanism analysis， the influence of different surface modification layers on the load-bearing performance of super heat-resistant aviation gear steel gears was revealed. The research results show that ordinary shot peening has no significant strengthening effect on the surface of super heat-resistant aviation gear steel gears. Super shot peening can significantly increase the residual compressive stress on the surface of super heat-resistant aviation gear steel gears. Compared with ordinary shot peening gears， the bending fatigue limit of super shot peening gears is increased by 36.04%； Super heat-resistant aviation gear steel gears are highly sensitive to the tooth surface roughness， gears with roughness Ra≤0.2 showing a 16.58% increase in bending fatigue limit compared with gears with a roughness of 0.3≤ Ra≤0.4. In the bending fatigue test， the microstructure of carburized layer near the surface of the gear is high-carbon martensite and finely dispersed granular carbides， and it gradually transits to ultra-low carbon flat noodles martensite with the increase of carburized layer depth. The failure mode of the test gears is fatigue fracture of the gear teeth， with clear fatigue bands visible on the fracture surface. The fatigue cracks of the super shot peening gears all originate from the sub surface of the tooth root fillet， while the fatigue cracks of ordinary shot peening gears mostly originate from the surface of the tooth root fillet.