This research reported the isolation, purification and characterization of thermostable a-amylase enzyme from Bacillus TULH. Studies on the a-amylase production were carried out with a bacterial strain isolated from a hot water spring of gir national forest. The addition of yeast extract, Mgso₄, Vitamins and amino acids to the mineral medium shortened the lag period and improved the growth and a-amylase synthesis. The bacteria showed optimum growth at pH 6.8 and optimum temperature for the growth at 70°C. The optimal pH and temperature of the amylase activity were 6.8 and 68°C, respectively. The enzyme was found to be stable in the pH range of 5 to 8. Maximum a-amylase activity was determined in 2% starch. The enzyme was purified using 60% ammonium sulphate precipitation, dialysis and DEAE cellulose ion exchange chromatography which resulted in 11.1 fold purity with specific activity of 9.40 units/mg protein/ml. SDS-PAGE showed a single band equal to molecular weight of about 67 kDa which is equivalent to microbial amylases. The activity of the purified a-amylase increased with increasing enzyme concentration and incubation time.