For their high economic value of xylanase in biotechnological application, sixteen fungal strains were screened for their xylanase potentiality and the results revealed that: Aspergillus achuleatus DSM 63261 was the highest xylanase producer.  Aspergillus niger M2 and A. terreus  were also highest xylanase production.  Other strains were found in the moderate xylanase potentialities.  1% corn stalk conc. Was found as the best inducers between different cellulosic materials used for stimulating the enzyme biosynthesis. The addition of sugar cane molasse as carbon & energy source and the present of 0.042% of corn steep liquor and 0.2325% of KH₂PO₄ as nitrogen and phosphorus content in the production media were very necessary for highest xylanase secretion.  pH 4.0 and 7.5% inoculum level to the volume of the production media, 35°C, 200 rpm as agitation rate, and 96 hours were found as the suitable factors supported the enzyme biosynthesis.  Final purification procedure of A. achuleatus xylanase with sephadex G-100 revealed that, specific enzyme activity reached 455.5 units/mg protein with 10.6 purification folds and 21.2% yield.  Optimum enzyme activity was observed at pH 7.0 and 50°C.  The enzyme was stable up to 50°C for 1 hour and retained 95% from its maximum activity at 60°C and 45% at 80°C.  Thus this enzyme protein is a thermolabial one.  The enzyme was quite stable in the pH range of 6.0 – 8.0.  At pH 5.0 the enzyme lost 51% from its maximum activity and only 23% at pH 9.0, these results show the neutrality nature of the enzyme protein.  Only KCL between different matal salts induced the enzyme activity, but the other such as FeCL₂ and HgCl₂ were significantly inhibited the enzyme activity.  A. achuleatus purified xylanase was highly specific for xylan hydrolysis, which the enzyme donot succeeded to hydrolyze other substrates tested.  Rapid hydrolysis of xylan with A. aculeatus xylanase was present after one hour of hydrolysis.  At which 30% from initial xylan weight in the reaction mixture was present.  Finally, these results might show that A. achuleatus produced highly amount of xylanase under these conditions tested, which used significantly for xylan hydrolysed in different biotechnological applications.