In this study, nanographite (NG), as a lubricant additive, and polyimide (PI) were used to fabricate NG/PI composites via a hot compression molding process. The tribological properties of the NG/PI composites with different NG mass contents (0-10 wt%) were tested using a reciprocating ball-on-disc contact tribometer matched with a GCr15 rubbing pair. The thermal stability, surface hardness, and compression strength of the composites were discussed. The results revealed that a small quantity of nanofillers greatly reduced the friction coefficient and increased the wear resistance of the NG/PI composites. Despite a minor decrease in mechanical performance, the composite with 5 wt% of NG filler exhibited improved tribological properties; it showed a 55.63% reduction in the friction coefficient and a reduction of 97.39% in the wear rate compared with neat PI. Moreover, an increase in the glass transition temperature (T-g) of the NG/PI composites indicated the enhancement of their thermal stability and wear resistance. Scanning electron microscopy (SEM) analyses showed that the main wear mechanism of the composites was fatigue wear. These findings suggest that the 5 wt% NG/PI composite could be a significant contribution to the field of tribological engineering plastics.