Soybean mosaic virus (SMV) causes one of the most destructive viral diseases in soybean worldwide. Ninety-eight SMV isolates identified in the U.S. were classified into seven strain groups (G1 to G7). Three independent loci (Rsv1, Rsv3, and Rsv4) have been identified for SMV resistance. SMV strains G1 and G7 were used to characterize the reactions of 209 soybean genotypes to SMV. Fifty-four genotypes were resistant to G1 but susceptible to G7. Thirty genotypes were resistant to G1 but exhibited stem-tip necrosis following G7 inoculation. These 84 soybean genotypes presumably carry alleles at the Rsv1 locus. Thirty-seven genotypes were resistant to G1 and G7, indicating that they presumably carry Rsv4, Rsv1-r, or Rsv1-h or a combination of two resistance genes Rsv1Rsv3, Rsv1Rsv4, or Rsv3Rsv4. Seven genotypes were susceptible to G1 but resistant to G7, and may carry alleles at the Rsv3 locus. PI 507389 and PI 61944 developed stem tip necrosis after inoculation with G1 and a mosaic symptom when inoculated with G7, indicating that PI 61944 may carry the same Rsv1-n gene as PI 507389. The objectives of this research were to screen the resistant soybean genotypes with SMV G2-G6 to differentiate specific alleles of SMV resistance genes in these soybean genotypes. The results indicated that new alleles of SMV resistance gene were identified. Research was undergoing to confirm the new SMV resistance alleles by genetic study.