Xylan is the major constituent of hemicellulose. Due to the structural heterogeneity of the xylans, xylan-degrading enzyme systems include several hydrolytic enzymes. Xylanase（EC 3.2.1.8, 1,4-β-D-xylanase）can hydrolyze β-1,4-glycosidic linkages of the xylan backbone to produce short chain xylooligosacchrides of various lengths. Hence, endo-β-xylanase is the crucial enzyme component of microbial xylanolytic enzyme systems. A large number of bacteria and fungi are known to produce xylanases. Xylanases from microorganisms have attracted a great deal of attention in recent years because of their biotechnological potential application in various industrial processes such as food and feed industries. An important factor for efficient xylanase production is the choice of an appropriate inducing substrate, as well as optimization of the medium composition. Properties of xylanases are different due to various microorganisms. The highlights complex xylan structure, microbial xylanolytic enzymes including their production, properties and their application in industries was reviewed.