The nodule-specific expressed protein AsF259 which are homologous to the CCPs was identified in Astragalus sinicus,expressed in Escherichia coli (DH10B) to study the subcellular localization in onion epidermal cell and in Astragalus sinicus nodule. The real time qPCR was used to analyze the gene expression. Results showed that AsF259 protein was distributed in the cell wall,cell membrane and cytoplasm,and highly nodule-specific expressed in the nodules with the highest expression level during the crucial stage of bacteroids differentiation. AsF259 protein was co-localized with the bacteroids,indicating that AsF259 gene belongs to a novel member of NCR family and may play an important role in bacteroids differentiation,maintenance and nitrogen fixation.