Objective To understand the prevalence of antibiotic susceptibility, virulence and antibiotic resistance associated genes of 4 kinds of bacteria in a pig farm in Shaanxi Province. Methods Eighty five Escherichia coli, 93 Enterococcus, 33 Salmonella and 7 Staphylococcus aureus isolates that recovered from a pig farm in Fufeng County, Shaanxi Province, from 2015 to 2016, were tested for their susceptibility to 14 antibiotics by disk diffusion method. Some antibiotic resistance associated genes in Enterococcus and Salmonella, and some virulence genes in Enterococcus and S.aureus were detected by polymerase chain reaction (PCR). Results All S.aureus isolates were susceptible to gentamicin, amikacin, amoxicillin/clavulanic acid, cefoperazone and ceficidin. The rate (100.00%,7/7) of nalidixic acid resistant for S.aureus isolates was significantly (χ²=54.77,P<0.05) higher than that of other antibiotics tested for. All Salmonella isolates were sensitive to amoxicillin/clavulanic acid, cefoperazone and cefoxitin. The rates of trimethoprim/sulfamethoxazole (100.00%,33/33) and tetracycline (96.97%,32/33) resistant Salmonella isolates were significantly (χ²=5.83,P<0.05) higher than those of the remaining 9 antibiotics tested for. Seventy-four E.coli isolates resisted to tetracycline, and the rate (87.06%,74/85) of tetracycline resistant was significantly (χ²=4.68,P<0.05) higher than that of other 13 antibiotics screened for. The rates of amoxicillin/clavulanic acid and cefoxitin resistant E.coli isolates were lower than other antibiotics. The rate (97.85%, 91/93) of trimethoprim/sulfamethoxazole resistant Enterococcus isolates was the highest.The detection rate(47.13%,41/87)of aph(3′)-Ⅲ gene in Enterococcus isolates was the highest. The detection rates of aadA1 and aadA2 in Salmonella isolates were the highest, both were 84.85% (28/33). The detection rate(50.57%, 44/87)of Enterococci isolates virulence gene asal was the highest. The detection rates of sea, see and seb genes in S.aureus isolates were 42.86%(3/7), 42.86%(3/7) and 14.29%(1/7), respectively. Conclusion Antibiotic resistance situation of the 4 kinds of bacteria in the pig farm in Shaanxi Province was quite serious, and the majority of the isolates carried antibiotic resistance associated genes and virulence genes. The antibiotic application and monitoring should be strengthened to ensure the safety of pork from the source.