The genetic diversity within a set of 22 strains of Inonotus obliquus from 6 countries was assessed using SRAP marker. The number of polymorphic fragments detected per primer combination ranged from 20 to 52 with an average of 37.74. Twenty three SRAP primer combinations had generated a total of 868 bands of which 859 (98.62%) were polymorphic. The UPMGA cluster analysis revealed that the 22 strains of Inonotus obliquus could be divided into 4 groups with the genetic similarity of 0.68. Principal coordinate analysis (PCoA) clusters was consistent with the results of UPGMA. Its results confirmed the results of UPGMA cluster analysis. This is the first report of using SRAP marker as a tool for determining genetic variation among Inonotus obliquus.