Background: The rapid increase of drug resistance in conventional antibiotics promotes the discovery and development of antimicrobial peptides (AMPs), which are important components of natural immunity. Due to the specific action modes targeting for cell membrane, AMPs have become a promising substance for bacterium inhibitions barely with no drug resistance. Here we reviewed the structure characteristics related with bactericide actions, including peptides constituents, molecular length, molecular charges and so on. And we also summarized the common mode of actions of AMPs raised by researchers. The structure-mechanism relationship was discussed. The commonly used methods for mechanism study were also listed. Key findings and conclusions: The structures of AMPs were strongly related with its efficacy, such as constituents, molecular length, charges, secondary structures. The main mechanisms of AMPs were divided into membrane targets and intracellular targets. Some advanced and new techniques were applied in the mechanism study. Most of the existed mechanisms are still suppositional, and techniques were mainly focused on membrane-associated mechanism, only few of them were related with intracellular factors. Therefore, more new methods are expected to explore the authentic mechanisms and better results as well as more intracellular targets. This review provides a reference for future AMPs chemical modification and mechanism exploration.