Polycaprolactone (PCL) has been widely studied for biological applications. Biodegradable PCL fibrous scaffold can work as an appropriate substrate for tissue regeneration. In this letter, fluorescent nanodiamonds (FNDs) were prepared after surface passivation with octadecylamine. The FNDs were then mixed with PCL polymer and subsequently electrospun into FNDs/PCL fibrous scaffolds. The obtained scaffolds not only exhibited photoluminescence, but also showed reinforced mechanical strength. Toxicity study indicated FNDs/PCL scaffolds were nontoxic. This biocompatible fluorescent composite fibrous scaffold can support in vitro cell growth and also has the potential to act as an optical probe for tissue engineering application in vitro and in vivo.