Objective To evaluate in vitro antimicrobial effect of fosfomycin sodium single use and combination with other antimicrobial agents on clinically isolated Staphylococcus aureus (S. aureus), Klebsiella pneumoniae (K. pneumoniae) and Pseudomonas aeruginosa (P. aeruginosa) in China. Methods Combined antimicrobial susceptibility testing was performed with checkerboard method, minimal inhibitory concentrations (MICs) were detected by two-fold agar dilution method, susceptibility of S. aureus (n=113 strains), K. pneumoniae (n=108 strains), and P. aeruginosa (n=110 strains) isolated from 18 hospitals in China in recent three years was determined by single and combined antimicrobial susceptibility testing. Results MIC₅₀ value of fosfomycin sodium single use were all ≤ 32 mg/L against all tested strains, regardless of whether strains were resistant to other antimicrobial agents or not. The synergistic rate of fosfomycin sodium with levofloxacin, minocycline, oxacillin, and clindamycin against methicillin-resistant S. aureus (MRSA) was >43%. Synergistic rate of fosfomycin sodium with levofloxacin and imipenem against imipenem-nonsusceptible P. aeruginosa was >35%, synergistic rates of fosfomycin sodium with tested antimicrobial agents against imipenem-susceptible P. aeruginosa were all >35%. Conclusion Fosfomycin sodium still has good antimicrobial activity against common clinical drug-resistant bacteria, such as MRSA, extended-spectrum β-lactamase-producing K. pneumoniae and so on, it has synergistic effect with many other kinds of antimicrobial agents, suggesting that in the limited treatment of infection caused by drug-resistant bacteria, fosfomycin in combination with other antimicrobial agents may be a useful choice.