Due to the rapid advancement of mobile communication technologies, many educators believed that these new technologies will have a great impact on the way of learning. By effectively applying shortmessage services as Learning Content Delivery (LCD) methods provided by mobile phone system to deliver content using different Learning Content Representation (LCR) types, M-learning can be implemented accordingly. However, the most important issue is whether this way can really achieve good Learning Outcomes (LOs) and be accepted by learners. This paper will explore the restraint of Short- Term Memory (STM) of psychological learning process through technology-mediated learning theory on assessing LOs. The finding of this study is to match different LCR types with different LCD methods to fit with learners? different STM abilities would result higher LOs in M-learning environment.