Objectives The prevalence and drug resistance of Streptococcus agalactiae in dairy cattle with mastitis in Urumqi and its surrounding areas was investigated to provide reference for the scientific prevention and control of mastitis caused by Streptococcus agalactiae in local dairy farms. Methods 300 milk samples of dairy cattle with mastitis were collected from 5 large-scale dairy farms in Urumqi, the 12th Division of the Xinjiang Production and Construction Corps (XPCC), and its surrounding areas. Streptococcus agalactiae from the samples were isolated and cultured. PCR was used to identify the bacteria. The drug resistance of the positive strains isolated was analyzed with disk diffusion method. Results The isolation rate of Streptococcus agalactiae was 8.3%, and its resistance rate to streptomycin, penicillin, gentamicin, and ampicillin was all over 50%. Its sensitivity to vancomycin, cefotaxime, and norfloxacin was more than 60%. 7 strains of Streptococcus agalactiae isolated had multiple drug resistance. Conclusions It is recommended that dairy farms strengthen the daily management of feeding and scientifically use antibiotics, with priority given to using glycopeptides, cephalosporins, and quinolones for the prevention and control of mastitis caused by Streptococcus agalactiae in local dairy farms.