With the rapid development of mobile technologies, mobile learning has become a new trend in education. A better understanding of how to effectively use communication technologies to improve mobile learning is important. The purpose of this paper is to evaluate the media richness of various message delivery methods in the proposed m-learning environment based on media richness theory. Regarding the implications of the media richness theory, this study has identified four factors to evaluate a content in respect to the media richness among SMS, Email, and RSS: timeliness, richness, accuracy and adaptability. By the repeated-measures one-way ANOVA analysis, the results show that: (1) SMS has better performance than Email and RSS on content timeliness; thus SMS may be appropriate for immediate information delivery such as notifying or reminding of some time-sensitive matters; (2) Email has better performance than SMS and RSS on content richness and so may be applied in exhaustive information delivery; (3) RSS has better performance than SMS and Email on content accuracy and adaptability; thus RSS is more appropriate for supporting various front-end mobile devices to access and present the content in a mobile learning environment. According to the results, this study suggests developer and designer of an m-learning environment could adopt suitable information delivery medium to support the corresponding learning activities in a mobile learning environment; moreover, current general e-learning systems, particularly those intending to provide a mobile learning environment, can take advantage of RSS techniques to support mobile access and achieve the goal of mobile learning anytime and anywhere. (Contains 5 tables and 2 figures.)