The pathogenesis of bronchiectasis cannot be explained by a single cause. The current model is a vicious cycle of inflammation and altered response to infection. This cycle depends not only on the type and virulence of the pathogen but also on the host immune response. In this response, too much or too little can damage the airways or fail to clear the pathogen, thus increasing the probability of further infection. This review describes the changes and advancement in the pathogenesis of bronchiectasis, including mechanisms of injury and host factors.