The present communication reports on the rapid preparation of 1,5-diaminoanthraquinone nanofibers (DAAQNFs) on a large scale by a reprecipitation method and their subsequent decoration with small platinum nanoparticles (PtNPs) using tannic acid (TA) as a reducing agent. It suggests the resultant PtNP/DAAQNF composites exhibit a good catalytic activity toward reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by NaBH4. It also suggests that the composites exhibit higher catalytic activity than the PtNPs due to that the DAAQNF support may play an active part in the catalysis, yielding a synergistic effect. The possible mechanism involved has also been discussed.