This study developed a wearable mixed reality (MR)-based mobile learning system and applied it to museum learning activities to explore whether the proposed system can effectively improve university students' learning outcomes, situational interest, and cognitive load. Four museums were selected as the informal learning sites, and 64 university students were randomly divided into the experimental group (using the wearable MR-based mobile learning system) and the control group (using the conventional mobile learning system). The results show that in the retention and comprehension dimensions of the learning outcome, the experimental group has significantly better learning performance than the control group. The experimental group showed improvements in almost all dimensions of situational interest, except for the challenge dimension, while their extraneous cognitive load was reduced. Furthermore, this study found that the proposed system has a positive influence on museum learning in higher education, and has good potential for improving the conventional mobile learning system and enhancing students' learning performance. The findings of this study can provide a reference for future research on the possibilities of using wearable devices for museum education.