Tannin acyl hydrolase is an industrially important enzyme that is mainly used in the food and pharmaceutical industry. The present work has been taken up with a view of exploring the possibilities of using Agriculture by products for the production of tannase and optimizing condition require to get maximum production using Aspergillus  flavus, Trichoderma viride and Penicillium chrysogenum was selected and optimized for Tannase enzyme production in solid state fermentation using cheaper sources of paddy straw. Tannase production has been evaluated using solid-state fermentation (SSF) at different temperatures, pH, and incubation time. Optimum fermentation conditions of pH, temperature and Incubation period for Tannase production were found to be 5.5 and 30°C at 96 hrs. Thus the present study proved that the Penicillium chrysogenum  produced tannase shown in crude activity 17.0 (U/g/min), Ammonium sulphate precipitation 27.0 (U/g/min), Dialysis 34.0 (U/g/min), Column Chromatography 43.0(U/g/min)  and gallic acid content  (0.18 mg/gm )was determined by using HPLC method. The molecular structure of Gallic acid (Rt.6.55 min) was confirmed by using Gas Chromatograpgy with Mass Spectrophotometer (GC-MS) method.