To enhance the machining efficiency and quality of the nanogrooves on single-crystal SiC surface, an in-plane ultrasonic vibration was introduced into the conventional nanoscratching (CNS) based on the atomic force microscopy, developing into the ultrasonic assisted nanoscratching (UANS). Experimental results indicate that the application of ultrasonic vibration significantly improves the depth/width of the nanogrooves and enhances the material removal volume across all applied normal loads, compared to CNS. Furthermore, the nanogroove depth/width exhibited a positive correlation with increasing ultrasonic amplitude, while an inverse relationship was observed with increasing scratching speed. The contact area at the tip-workpiece interface was identified as a critical factor governing the resultant groove dimensions. Subsequently, SEM analysis of the AFM tips revealed that UANS effectively mitigated tip wear, which can be attributed to the reduction of the interfacial friction induced by the transient contact dynamics. The ultra-small contact area and ultra-short cutting duration effectively inhibits stress transmission into the subsurface lattice, thereby preserving the generation of the subsurafe damage (e.g. dislocation and stacking faults) in the SiC material. This study confirms that ultrasonic vibration assistance substantially enhances both the efficiency and quality of nanogroove machining, thereby presenting a novel strategy for high-efficiency, low-damage nanofabrication.