A $eta$-xylosidase was purified from the culture of Trichoderma sp. SY. The ten-day-old culture filtrate was concentrated, followed by ion-exchange chromatography and gel filtration chromatography. As a result, $eta$-xylosidase was finally purified about 53-fold and appeared as a single band by SDS-PAGE. The optimum pH and temperature were 5.0 and $55^{circ}C$, respectively, and the molecular weight about 80 kDa. The purified $eta$-xylosidase was found to be inhibited by various metal ions but not inhibited by xylose.