Ralstonia solanacearum, a widely distributed and economically important plant pathogen, was characterized by ion-exchange chromatography (IEC). Ralstonia solanacearum was chromatographed on a TOYOPEARL SuperQ-650 C column (200 mm x 4. 6 mm i. d. ) with gradient elution by A (0.02 mol/L piperazidine-chlorhydric acid buffer (pH 8.0) ) and B (A + 1 mol/L NaCl). The pure culture of R. solanacearum was separated into three fractions on a SuperQ-650 C column. They were found all belong to R. solanacearum after the fractions were identified by other biochemical methods. Because of their ability to oxidize 3 disaccharides (lactose, maltose and cellobiose) and 3 hexose alcohols (mannitol, sorbitol and dulcitol), they are classified as biovar III of R. solanacearum. Once the mobility was scaled using microscope and the pathogenetic ability was measured with 2,3 ,4-triphenyltetrazolium chlorid (TTC) medium, the two fractions were in different states. The results are very important to elucidate the multi-states of R. solanacearum and the mechanism of R. solanacearum's pathogenetic mutation.