This study presents a numerical model that incorporates the actual micro morphology of sealing lip and rotating shaft to elucidate the sealing behavior in high-speed rotating lip seals operating under mixed lubrication conditions. The model explores the intricate interplay between hydrodynamics at the interface, macro-scale solid mechanics, micro-contact mechanics of surfaces, and the heat generated by friction at the lip. Based on this model, this paper quantitatively predicts the leakage rates and friction torque under various operating conditions and lip seal structural parameters, shedding light on the influence of high-speed frictional heat on sealing performance.