Acinetobacter baumannii is Gram-negative non-fermentative pathogenic bacteria, which exists widely in the hospital environment and has become one of the important pathogens of hospital-acquired infection. Due to the widespread use of antibacterial drugs, the infections and outbreaks caused by multi-drug resistant Acinetobacter baumannii have brought great challenges. Recent research indicated that type VI secretion system (T6SS) might be related to the pathogenicity of bacteria. In this review, we summarized the research progress of T6SS and T6SS-related proteins (haemolysin-regulated protein, Hcp), which provided the basis for further investigation about pathogenesis of Acinetobacter baumannii.