To investigate the presence of plague phages in dogs, we isolated one plague phage strain from 15 anal swab samples from Chinese field spaniels, an indicator animal species in the source area of newly emerging wild rat plague in Yunnan Province, China, in April 2024. Isolation and purification of the phage strain were performed using the double-layer agar plate method. Titer was determined using the spot plate and drop methods, and a one-step growth curve was plotted using the classical method. Observations through transmission electron microscopy showed that the isolated plague phage (HQG8) has a typical tadpole morphology, consisting of an icosahedral head, an intermediate annular neck ring, and a long contractible tail sheath. HQG8 showed lysis of multiple Yersinia pestis strains at 28 °C and 37 °C, and it exhibited lytic activity against Shigella flexneri 2a at 22, 28, and 37 °C. The optimal multiplicity of infection-ratio of phage particles to host bacteria at the time of infection for HQG8 was 0.1. The incubation and lysis periods were approximately 40 min and 140 min, respectively, and growth entered the stabilization period after 180 min. Genomic analysis showed that the total length of the gene sequence of HQG8 is 35,876 bp. To our knowledge, this is the first study to isolate the Y. pestis bacteriophage from domestic dogs during a wild rodent plague in China. Although genomic analysis revealed that HQG8 is highly similar to previously reported phages infecting Enterobacteriaceae, its isolation from a canine host within a plague ecosystem is unprecedented. Our findings provide new insights into the ecology of plague phages and highlights dogs as potential reservoirs for bacteriophages that may influence the dynamics of Y. pestis in natural foci.