Abstract: Studies on drug susceptibility, serotype and molecular epidemiology of Streptococcus from swine were investigated through biochemical reaction test, drug susceptibility test, PCR typing, PCR test of virulence factor genes and animal test assays. 97 strains of Streptococcus were isolated from heart blood, liver, lymph node, brain and joint of swine in China. Drug susceptibility test for 97 strains showed their resistance patterns were different, but their drug resistance rate to cephalosporin V and ciprofloxacin is lower than 5℅ respectively. PCR typing assay indicated that 26 strains were Streptococcus suis including 1 serotype 1 strain, 16 serotype 2 strains, 4 serotype 7 strains and 5 other serotype strains. The genotypes of their mrp, epf and sly were identified by PCR method as well. Result of mouse virulence test showed that the genotypes of streptococcus, which were lethal to all of the mice, were mrp+, epf+ and sly+ serotype 2 strains. One serotype 2 strain and one serotype 7 strain could reproduce typical swine streptococcosis.