Three bacteria strains resistant to arsenic(Ⅲ), named WK_21, WK_31 and WK_32, were enriched with 2×10-3 mol/L NaAsO2 and isolated on plates from the three pieces of rock (or soil) samples from Yangshancdhong mine tailing dumps of Tonglin in Anhui Province. These strains are all aerobiotic and have a high resistance to arsenic(Ⅲ), and are respectively resistant to the most arsenic(Ⅲ) of 32, 56 and 50 mmol/L after being cultivated for 48 hours on the solid LB medium. Through a study of their growth in different concentrations of arsenic(Ⅲ), the authors found that the arsenic of low concentration made a small impact on or even slightly promoted the bacteria's growth and that, when the concentration of arsenic(Ⅲ) increased, the suppression of the growth was clearly enhanced. Based on a careful observation of the three strains' morphological characteristics, physiological and biochemical characteristics and 16S rDNA sequences, the authors identified the three strains as Arthrobacter sp., Rhodococcus equi and Paenibacillus sp., respectively. Since these arsenic_resisting strains were isolated from the soil samples of mine tailing dumps, the data obtained are likely to provide valuable materials for further studies of the environmental microbial remediation in the same kind of areas polluted by heavy metals and the mechanism for microbial resistance to heavy metals.