Does visiting Mainland China alter Taiwanese students’ evaluation of Taiwan’s democracy? This question greatly concerns democratic supporters globally. Therefore, 477 Taiwanese young adults participating in Mainland China exchange programmes were recruited for this study. Social contact, social identity, political socialisation and rational choice theories were introduced to formulate four hypotheses. The results indicated that, among the three dimensions constituting the democracy evaluation following their exchange to Mainland China, the Taiwanese students showed increased positive evaluations in democratic support and degree of democratisation. Furthermore, positive evaluations for satisfaction with democracy decreased. The evaluation of Taiwan’s democracy, formed by aggregating these three dimensions, indicates that this index decreased in 27.54% of students, increased in 29.24% and remained unchanged in 43.22%. After visiting Mainland China, students exhibit a tendency towards ethnically identifying as Taiwanese, or have a worse impression of China, or have greater political trust towards Taiwanese officials, or show a lower preference for the strongman rule, leading to a more favourable evaluation of Taiwan’s democracy.