Objective To investigate the mutation patterns and phylogenetic relationships of the plo gene in strains from different hosts, and provide feasible methods for characterizing the strain-host association.Methods The plo gene was amplified using PCR from 14 strains isolated from goats, 2 strains from pigs and 2 strains from sheep, and sequenced and spliced.Multiple sequence alignment and phylogenetic analysis were performed on the plo complete gene obtained from 18 strains, as well as the plo gene downloaded from Gen Bank, and their coding products.Results The plo complete gene was obtained from 18 isolates, and the homology was higher than 95%. The plo gene had three types of point mutation. Type Ⅰ was composed of strains from bovines and a horse, with 10 consistent mutation sites; typeⅡwas composed of strains from pigs and a dog, with 22 consistent mutation sites; and type Ⅲ was composed of strains from goats, sheep, a chamois and a forest musk deer, with 32 consistent mutation sites. The mutation sites were distributed dispersedly in most regions of the plo gene. These mutations produced 16 sense mutations, resulting in three corresponding point mutation patterns of PLO protein. Trueperella pyogenes(T.pyogenes) was divided into four branches in the plo complete gene phylogenetic tree established by the neighborjoining method(NJ). The bovine strains and a strain from horse were clustered into GroupⅠ, the strains from pigs and a dog into Group Ⅱ, the strains from goats, sheep, a chamois and a forest musk deer into Group Ⅲ, and the one strain from sika deer into Group Ⅳalone. Different from plo genotyping, the one strain from sika deer was clustered into Group Ⅲ in the PLO phylogenetic tree.Conclusion The plo gene exhibits host-associated mutations. By constructing phylogenetic trees of the plo complete gene and PLO complete sequence, strain-host association can be demonstrated, indicating that the plo gene and PLO sequence are useful molecular markers for characterizing strain-host association.