This study integrates augmented reality (AR) technology into teaching activities to design a learning system that assists junior high-school students in learning solid geometry. The following issues are addressed: (1) the relationship between achievements in mathematics and performance in spatial perception; (2) whether system-assisted learning can improve the spatial perceptions of students; (3) whether students with high, average and low academic achievement learn effectively after taught with system assistance; (4) system usability; (5) system task load; and (6) the relationship among various factors. Study participants were 76 students from Tainan City, Taiwan. Qualitative and quantitative data are obtained using pre- and post-system-assisted learning paper-pencil tests, a system usability scale, National Aeronautics & Space Administration Task Load indeX, and observations and focus group interviews. Analysis results indicate that students' math scores and spatial perception during the test closely correspond to each other. Additionally, system-assisted can improve the spatial perceptions of student. Regarding group differences related to the significance of impact, students with average and low academic achievements exhibit small and medium levels of effectiveness, but are insignificant in high academic achievement students. As for system usability, students with low academic achievements demonstrate a positive attitude toward the intensive programs provided by the system. However, the correlation between students' learning effectiveness and system usability/task load is low.