Transfer of Micropolyspora internatus into the genus Saccharomonospora as “Saccharomonospora internatus comb. nov.” was proposed by Kurup and Greiner-Mai, but the nomenclatural change has not been validly published. Although the inclusion of M. internatus in the genus Saccharomonospora has not being established, the synonymy of “Saccharomonospora internatus” and S. viridis was proposed by Greiner-Mai. A number of recent publications regarded M. internatus as a synonym of S. viridis, but the name M. internatus is still used in some cases instead of S. viridis. This is because of the complicated history of M. internatus and S. viridis, but it is different from the generally accepted view of prokaryotic taxonomy. To clearly verify the synonymy of M. internatus and S. viridis, a literature review and experimental verification were conducted in this study. Based on the genomic and phenotypic characteristics obtained in this study, the synonymy of the two species was obvious. The emended description of S. viridis is given.