The study aims to explore the effects of applying design thinking on vocational students’  mechanical  engineering  learning  performance  in  a  knowledge  building environment. Purposes of the study are also to understand the relationship among students’ conceptions of learning, approaches to learning, and self-efficacy for learning mechanical engineering;  and  the  relationship  between  their  co-regulated  learning  and  learning engagement. The participants in this study were 30 vocational students who major in mechanical engineering. Adopting quasi-experimental design for research method, the participants were separated into experimental group (n = 18) and control group (n = 12). The experimental group was applied design thinking teaching in a knowledge building environment (knowledge forum platform) course; while the control group was applied only a knowledge building environment course. The duration of the teaching experiment was 3 hours a week for 8 weeks. First week and the last week during the course respectively measured for pre-test and post-test questionnaires. The main instruments of research include questionnaires: conceptions of learning, approaches to learning, learning self-efficacy, co-regulated learning, learning engagement, design thinking, preference of knowledge building environment, discussion strategy. PLS-SEM and Mann-Whitney U test were used as the main data analysis methods in this study. The results show that vocational  students’ lower  learning  conceptions  negatively  predicted  their  learning performance,  students’ higher  learning  conceptions  positively  predicted  their  deep strategy, deep motivation, and surface motivation, and students’ deep motivation and deep strategy positively predicted their self-efficacy for learning mechanical engineering. In co-regulated learning, students’ “planning regulation” positively predicted their cognitive engagement, students’ “effort regulation” positively predicted both of their behavioral engagement  and  emotional  engagement,  students’  “help-giving  and  help-seeking regulation”   positively   predicted   their   learning   performance,   however,   students’ “evaluation  regulation”  negatively  predicted  their  learning  performance. As  for  the differences between applying design thinking teaching or not, experimental group more recognized that peers’ ideas are important than control group did in knowledge building environment. The  experimental  group’s  perception  of  anxiety  during  face-to-face discussion was significantly lower than the control group. The experimental group’s perceptions  of  comprehension  and  interaction  during  face-to-face  discussion  were significantly higher than the control group. In addition, the experimental group tended to have more cognitive, behavioral, emotional, and social learning engagement than the control group did. Moreover, the social network analysis indicated that degree centrality and closeness centrality of experimental group were significantly higher than control group. Finally, as the 12-year basic education curriculum guidelines were officially implemented in Taiwan, this study proposed some suggestions for the instruction design, and hopefully implemented the teaching of core competencies in vocational high school.

Keyword：Knowledge Building, Design Thinking, Conceptions of Learning, Approaches to Learning, Self-Efficacy, Co-Regulated Learning, Learning Engagement