As one of the most influential factors to the development of mobile commerce, security has always been the big concern of many organizations and users all over the world when interacting on mobile devices. The situation in Vietnam revealed that despite the early implementation of mobile commerce application, its development to now has yet made any remarkable progress. Moreover, such expected online commerce as trading, payment on mobile devices have not been widely exercised. Weak security on mobile devices in Vietnam is said to be the reason for this situation, which generates worry among users and even service providers in dealing with trading transactions. The article provides the classification of the current most popular forms of possible risks for mobile devices. Furthermore, it also suggests some relevant prevention methods to promote the development of security and-mobile commerce in Vietnam.