Conventional activated sludge process and its derivative process have been regarded as a representative and valuable process for biological water treatment because of their simple operation and mature technology. Nevertheless, several drawbacks hinder their wider applicability, in which the high operating energy costs and poor microbial tolerance for toxic substances. Bacterial-algal symbiosis biofilm technology has been given increasing attentions since their high nutrients removal under the condition of less aeration and the excellent suffertibility of load and toxicity. The motivation of this study, therefore, to discuss the formation process of bacterial-algal biofilm and the mechanism of pollutants removal, to introduce the influence factors for the biofilm formation and advantage of the engineering application. We also summarize the insufficient and analysis the further prospects of the bacteria-algal biofilm to provide technical support for the popularization of bacterial-algal symbiotic biofilm.