The aim of this paper is to study influence of the certain production parameters of α-amylase by Bacillus circulans ATCC 4516. Optimization parameters of α-amylase were carried out with solid state fermentation (SSF). Solid waste from rice bran used as the basic nutrient source. Supplementation with carbon and metal salt sources decrased the enzyme production. Certain fermentation parameters involving incubation time, incubation temperature, inoculum level, initial pH and extraction medium were studied separately. Maximal amount of α-amylase production (2716.9 ± 35.9 U/mg) was obtained inoculum level 25%, initial pH 7.5 at 37oC for 48 h with supplementation of ammonium chloride.