<p>Nickel-based superalloy (GH4169) is a typical difficult-to-machine material with high strength and low thermal conductivity, which often leads to severe tool wear and surface damage during machining process. In order to improve its machinability, ultrasonic vibration-assisted turning (UVAT) technology has been introduced. At present, research on the transient changes of cutting force within a single cycle of axial ultrasonic vibration is still limited. This article establishes a transient cutting force prediction model for UVAT nickel-based superalloy based on non equidistant shear band theory. This model comprehensively considers the dynamic changes of cutting thickness and shear angle during the ultrasonic vibration cycle. Unlike traditional models that focus on average cutting force, the method proposed in this paper describes the dynamic evolution of cutting force within a single ultrasonic vibration cycle. By comparing the predicted data with experimental results, it was verified that the model can accurately predict changes in cutting force within a single cycle. This work provides theoretical support for ultrasonic vibration machining of nickel-based superalloys and other difficult-to-machine materials.</p>