Products such as vegetables and fruits in markets in Taiwan have small green labels denoting that they are traceable agricultural products. This study investigated the effect of social influence and system characteristics on perceived usefulness (PU) and perceived ease of use (PEOU) regarding the Taiwan Agricultural and Food Traceability (TAFT) system. This study also examined the effects of PU and PEOU on attitudes and reuse intention, and employed confirmatory factor analysis and structural equation modelling to test the hypotheses. Questionnaires were developed and the measurement items were based on an extensive review of related studies to ensure content validity in addition to items from an original scale. Four hundred questionnaires from older adults were collected through a quantitative survey. The respondents were all aged between 50 and 90 years, with an average age of 57.61 years. Almost one quarter (21.8%) of respondents had experiences of using traceability quick response (QR) codes in 2016. Regarding purchase experience, 59% of the respondents had experiences of purchasing agricultural products using traceability QR codes. The results revealed that whereas subjective norms, image, and visibility have a positive effect on PU, information quality and system quality affected the PEOU of the TAFT system. Moreover, trust has a positive influence on reuse intention. A healthy diet plays a crucial role in the health promotion activities of elderly people. The findings could help those involved in the TAFT system improve their understanding of the attendant factors of PU and PEOU and promote positive attitudes in elderly people about this system, thereby increasing their reuse intentions.