Linear and circular plasmids were investigated among the 44 strains of the rice plant endophytic Streptomyces. By pulsed-field gel electrophoresis, 60 kb-410 kb linear plasmids were detected from the 8 strains and four of which might contain the conserved telomere replication gene tap, resembling that of soil Streptomyces strains, indicating that the diversity of Streptomyces linear plasmids was not affected by the unique environment of the rice plant. By alkaline method, 6 kb~60 kb circular plasmids were detected on gel from the 13 strains.