Acidithiobacillus ferrooxidans is able to synthesize intra-cellular electron-dense magnetite, which formed by BCM method in Acidithiobacillus ferrooxidans. The whole genome of the type strain Acidithiobacillus ferrooxidans ATCC 23270 was analyzed by bioinformatics and some homolog genes of functional ones in magnetotactic bacteria were available. This study analyzed the different concentration of Fe2+ stress response of mpsA, magA, thy and mamB gene by using real-time PCR analysis. Temporal genes expression profiles were examined in cells subjected to different concentration of FeSO4·7H2O stress, they reached to high expression under 150~200 mmol/L FeSO4·7H2O stress. With this new method study, it is possible that we could do deeper research to generate a comprehensive description of the mechanism that how Acidithiobacillus ferrooxidans synthesize the magnetic particles.