Black phosphorus (BP) as an emerging two-dimensional material has been found that it possesses excellent potential applications in a variety of fields. Recently, it has been also proved that BP can exhibit excellent lubricating properties when it was used as water- or oil-based lubricant additive. In the present work, in order to explore the tribological properties of BP nanoflakes used as the solid filler in polytetrafluoroethylene (PTFE), spark plasma sintering (SPS) was used to prepare the BP/PTFE composites. Meanwhile, in consideration of the characteristics of BP easy to be oxidized, BP was actively oxidized to prepare the degraded BP (d-BP)/PTFE composites. Then Si3N4 balls were used as counterpart balls to conduct tribological experiments. The results of tribological experiment showed d-BP/PTFE composites with a d-BP content of 5 wt.% exhibited the best tribological properties under dry sliding and water environment condition. The characterizations and analyses of the counterpart balls and worn surfaces demonstrated that a layer of transfer film composed of phosphorus oxide reduced the coefficient of friction (COF) and wear rate. Besides, when the composites were used in an environment of water, the phosphorus oxide on the surface can dissolve in water and form a hydrogen bond network and thus further reduced friction.