The purpose of this study is to explore the ability indices of VR (virtual reality) technology when it is applied to assist the teaching of a welding practice course, develop a VR welding course as the basis of course planning and teaching design, and implement experimental teaching to verify its effectiveness. On the basis of a literature review and focus group interviews, initial ability indices of a VR welding course were proposed. Then, 15 experts from VR- and welding-related specialties were invited to form a consulting team to determine "the ability indices of the VR welding course" according to the results of a Fuzzy Delphi expert questionnaire. Moreover, the results of an ANP (Analytic Network Process) expert questionnaire were used to understand the relative importance of the ability indices of the VR welding course, as well as the relative feasibility of VR-assisted welding teaching, in order to develop a "VR welding course", in which 34 first-grade students of the welding practice course were taken as the research objects during the implementation of experimental teaching. The qualitative research and analysis results are as follows: (1) the VR welding course includes 8 ability indices and 30 evaluation indices; (2) the item with the highest feasibility in VR-assisted welding teaching is "welding construction", followed by "map reading and drawing"; (3) best feasibility of VR technology "Interaction" in assisting welding teaching; (4) the relative importance of the ability indices of the VR welding course is the greatest for "welding construction", followed by "welding inspection"; (5) the VR welding course students express significant positive responses to the learning of ability indices and ability demonstration; (6) the majority of students express significant positive learning satisfaction with VR-assisted welding course teaching. This study puts forward a set of rigorous models for the construction of ability indices for a VR course and course development. It can provide a reference for introducing VR-assisted teaching to related welding courses that are run by universities of science and technology in Taiwan. Furthermore, such VR courses can offer students a safe, diversified, and efficient learning environment. [ABSTRACT FROM AUTHOR]