Abstract: Due to the existence of drug absorption, distribution and metabolism, the occurrence of lower concentration of antibacterial agents than the minimal inhibitory concentration (MIC) is unavoidable in the course of antibacterial drug treatment, i e. sub-MIC. Several studies have showed that sub-MIC of antibiotics don't kill bacteria, but affect a variety of biological effects with strain specificity and drug specificity, including bacterial resistance, adhesion, movement and toxin release. Sub-MIC of antibiotics could affect the pathogenicity of bacteria and the treatment outcome of clinical infections, showing great clinical significance. In this review, the effect of sub-MIC of antibiotics on bacterial resistance and pathogenicity was reviewed, so as to provide reference for related researches.