Through collecting of nodule bacteria on peanut, separation and purification ofbacteria strains, and experiment of inoculating pot cultivated plants of former host varieties, the best strains of bacteria have been screened out. The best combinations of bacteria and host were achieved and crop yield was increased by artificial inoculation. In order to examine the stability of effect of the best strains, successive field test and experiments on pot cultivated plants were carried out. Results showed that the best strains of bacteria were stable. Crop production in field test and pot cultivated plants were all increased. More effects were achieved if a combination of two or more bacteria strains inoculated. This provided a theoretical foundation for introducing fine bacteria and combine inoculation.