Abstract: Bacterial biofilm is a biopolymer matrix-enclosed bacterial population adherent to biotic or abiotic surfaces. This adaptation has been implicated as a survival strategy. Most of bacteria can form biofilm under proper conditions. Antibiotics are generally not very effective against organisms embedded in biofilms （sessile bacteria） in comparison with free-floating organisms （planktonic bacteria）. This was one of the important reasons why infections were difficult to treat nowadays. How to form the biofilm, drug resistance mechanism and diseases caused by bacterial biofilm were conclude in this paper. The effective control methods were discussed. The information was useful to direct using antibiotics reasonable and developing new drugs.