Dental caries is a common oral disease that does great harm to human beings. It is regarded as one of the most important three noncontagious diseases. Currently, the prevalence of caries in China has increased to 40%. Many researchers have studied the origins of caries, the techniques of diagnosis and therapy, and their prevention. Recently, researchers have paid special attention to illuminating the mechanisms of cariogenic bacteria using immunological, biochemical, and molecular biological techniques. Various germs virulent factors have been intensively studied. Several methods of immunization against dental caries have been proven effective.