Oral cavity is a complex and ever-changing environment. Living in oral cavity have to deal with sudden changes at any time in the environment to ensure its survival and normal physical activities. This is also the prerequisite of cariogenic bacterials when they play cariogenic virulence. Here is a review about research progress on how Streptococcus mutans withstand pressures in the oral environment, including changes in catabolic pathways, membrane remodeling and membrane proton translocating adenosine triphosphatase, urease and malate fermentation, gene regulation, and changes in protein.