Abstract: In order to assess the drug resistance, pathogenicity and the ability to induce calculus formation of Proteus mirabilis, Proteus mirabilis was isolated from the urine of canine with infectious calculus and hematuria. Gram staining, culture characteristics analysis, molecular biological identification, antimicrobial susceptibility tests, ability of biofilm and urinary calculus formation of Proteus mirabilis were performed. The results showed that the bacteria was gram-negative bacteria without spore and capsule, and were polymorphic, rod-shaped and globular. The bacteria could produce urease to decompose urea, had hemolyticcand migratory. The nucleic acid sequence of the 16 S rRNA gene of the isolated strain was 99.1%-99.4% homology with the reference strain, which proved to be Proteus mirabilis. The isolated strain was only sensitive to the fourth-generation cephalosporin antibiotic cefepime and resistant to other kinds of drugs. The isolates could form a biofilm that produces a large amount of urine crystals. It indicated that Proteus mirabilis from canine had high drug resistance and pathogenicity, which could induce calculus formation and seriously threatened to human health.