To determine the types,signal peptide,and conserved motif of the type Ⅵ secretion proteins (Tss) in Xanthomonas campestris pv. raphani 756C ( Xcr),and to provide an important theoretical guidance for clarifying the Tss of the other Xanthomonas pathogen,Tss sequence of Xcr from the protein databases was searched using keywords,and the conserved domain was searched using SMART online.The signal peptide,transmembrane domain structure,the tertiary structure and conserved motif were analyzed.Meanwhile,the genetic relationships was analyzed using comparative Tss in Xcr and homologous sequences of other species.There are three Tss in Xcr ,namely TssA,TssB,TssC,which have more than 50% helical secondary structure and only TssC contains the typical signal peptide sequence.All the 3 Tss positioned in the plasma membrane,and each has 3 conserved motifs.Based on the genetic analysis of Tss,it is suggested that Xcc and Xca are closely related to Xcr.