In order to remove nitrate from groundwater at acid in-situ leach uranium mine，nitrate reducing bacteria communities were enriched from soil or rock samples in different areas by enrichment reaction system, and their reduction effect on nitrate in the groundwater was investigated. The results showed that three groups of bacteria communities with nitrate reduction capability were enriched, but only the group of bacteria enriched from the core sample at a decommissioned acid in situ leach uranium mine in Northwest China could adapt to its acidic uranium contaminated groundwater environment and had good capability of nitrate reduction. In?the?meantime，this community could reduce the nitrate concentration in the groundwater from 100 mg/L to 1 mg/L within 10 d, pH increased from 3.0 to 5.0 approximately，and its dominant bacteria were Tumebacillus, which accounts for 31.62%.