ObjectiveTo explore the risk factors for nosocomial methicillinresistant Staphylococcus aureus (MRSA) infection, so as  to provide a scientific basis for  taking effective measures to reduce nosocomial MRSA infection rates.Methods1:1 casecontrol study was performed, 108 pairs of research subjects were included in the research. Questionnaires were designed to study the history of case and control data. Multivariate nonconditional Logistic regression and chisquare test were used to analyze the data.ResultsAnalysis showed that the following factors were associated with nosocomial MRSA infection:  old age (≥ 65 years old, P= 0.013), length of stay in hospital (P<0.001), the types of underlying disease (P<0.001), the number of invasive procedures (P<0.001), broadspectrum antimicrobial  use(P<0.001), types of antimicrobial agents (P= 0.004) and duration use of antimicrobial agents (P<0.001). Multivariate analysis showed that the main risk factors related to nosocomial MRSA infection included length of stay in hospital (P<0.001), the number of invasive procedures (P= 0.001), types of used antimicrobial  (P= 0.001) and duration use of antimicrobials  (P<0.001).Conclusion Risk factors for nosocomial MRSA infections are long length of stay in hospital , frequent invasive operations , and longterm  as well as multiple use of broadspectrum antimicrobial agents.