This study examined two mediators of university students' behavioural intention to use digital platforms in the context of science service learning in Taiwanese universities. Based on the technology acceptance model (TAM), we proposed two cognitive variables as antecedents, self-efficacy and science trust, to verify their influences on students' behavioural intention. We further investigated two mediators, perceived usefulness and perceived ease of use, to examine to what extent they had effects on students' intention. Questionnaire data were collected from 282 university students who participated in a science service project. A structural equation model (SEM) procedure was used to test the direct and indirect relationships between the variables. The results showed that both self-efficacy and science trust had direct influences on perceived usefulness and perceived ease of use. The two mediators also had direct effects on students' behavioural intention. Nevertheless, as a mediating variable, only perceived ease of use effectively mediated the relationships between both self-efficacy and science trust and students' behavioural intention. Findings of this research could provide some suggestions to enhance students' behavioural intention for institutions where science service learning is a required project/programme.