Xylanase (E.C 3.2.1.8) is a widespread group of enzyme which can catalyze the endohydrolysis of 1,4-beta-D-xylosidic linkages in xylan. Xylanase has a wide application in industrial processes. In this study, the total RNA was isolated, the mature xylanase gene was obtained from Aspergillus niger C3486 by RT-PCR. To achieve secretive expression, pET32a (+) was used as expression vector, and the cloned gene was expressed in E. coli BL21 (DE3). After induction by IPTG, a large quantity of xylanase was produced with xylanase activity. With the analysis of bioinformatics, this xylanase contains a preceding peptide. Moreover, it has a typical conserve domain of xylanase. Predicted by Web site online, the xylanase is globulin, and its super structure contains many beta-sheets.