This study is mainly concerned with friction and wear properties for the piston ring of non-lubricating air compressor which made of PTFE-polyimide composites. At the PTFE and polyimide alone mixture specimens, PTFE80%-polyimide20%, which shows the lowest mean friction coefficient and specific wear rate at 0.94m/s sliding speed. In case of the specific wear rate, copper30% specimen shows the lowest value of 2.537-5(mm3/Nm) in all specimens. It considered that the friction coefficient is affected by generating speed and quantity of wear film. In case specific wear rate, it is attributed to the fact that the surface hardness of wear film is proportioned to specific wear rate.