IAA-producing strains were isolated from fluvo-aquic soil, out of which the strain JX15 showed the highest and most stable IAA excreting ability (22.55 μg/ml in 20h cultivation), combining additional phosphate-dissolving capability as well. Based on morphological, part of the physiological and biochemical characteristics and 16S rRNA sequences analysis, it was identified as Bacillus megaterium (GenBank Accession No. JX424613). Single factor tests were designed for preliminary study of the optimized conditions for the strain growth and fermentation. Results showed that the optimum condition for growth was consistent with that for excretion. The optimal culturing conditions for both growth and IAA secretion were pH 7 - 8，filling volume 50 ml/250 ml flask, incubation at 30℃ for 24 h, the best carbon and nitrogen sources were mannit and yeast extract. These results provided the experimental basis about the strains for the development of bio-organic fertilizer in the future.