Abstract:The analysis of constituents of protein subunits by protein SDS-PAGE technique in 11 sp ecies of Genus Arachis including 4 types of culti-species and 7 wild species showed that the band patterns may be divided into three sections, i.e. PⅠ, PⅡ and PⅢ presenting 5, 13 and 16 subunits respectively. The subunit number of diploid species was less than that of tetraploid species in general, but the difference of intraspecies or interspecies was mainly located in sections PⅡ and PⅢ. According to the indices of similarity of protein subunits, the relationship among four types (Virginia, Peruvian, Valencia and Spanish) of tetraploid culti-species (Arachis hypogaea) seemed mostly close to each other and A. monticola, the tetraploid wild species was related to one of them. Among four diploid wild species in Arachis section, A. cardenasii and A. batizocai were rather closer than ,A. correntina and A. duranesis and both A. villosulicarpa in Extranervosae section and A.pusilla in Triseminalae section were all distant relatives.