GH4169 is a classical superalloy material with good high-temperature strength, fatigue strength and corrosion resistance but also suffers from low surface hardness and poor wear resistance. Boronising treatment is one of the most effective approaches for improving the surface properties of GH4169 alloys. However, due to the high boriding temperature (i.e., above 900 ℃), the precipitated phase structure obtained during the aging treatment is destroyed, which affects the mechanical performance. In the present study, a GH4169 alloy was successfully boronised under ageing conditions, and a dense boride layer with a thickness of ~8.2 μm was obtained. The boride layer is composed of mixed Cr5B3, Cr2B, Ni2B and FexNi23-xB6 phases and has an ultrahigh hardness of 2 622.9 HV0.1. Additionally, ultralow wear rates (8.5×10-6 mm3 /N·m) are obtained when friction occurs against Si3N4 balls. The findings of the present study will be beneficial for the practical use of boronising treatment in nickel-based superalloys.