Objective: Music can relieve stress and reduce anxiety and is related to positive emo¬tions. Residents in a long-term care facility feel depressed because of loneliness, so nostalgic music can help soothe their mood. This study aimed to explore the relationship between nostalgic Chinese songs and the emotions of residents using facial recognition technology. Methods: This study used purposive sampling and the machine learning to train the samples. The facial recognition catches the changes among 7 emotions in 120s by the pretest without music and with the intervention of nostalgic music in an assisted-living facility in Taipei. A total of 25,200 pieces of data were collected in 15 cases and analyzed by a paired sample t-test, Wilcoxon signed-rank test, and Chi-square test. Results: The happy emotion significantly in¬creased when listening to nostalgic Chinese songs (pre-test Mean = 0.15, SD = 0.12; post-test Mean = 0.27, SD = 0.15; p <.05) but the surprised emotion was significantly reduced (pre-test Mean = 0.04, SD = 0.03; post-test Mean =.02, SD = 0.01; p <.05) by the paired sample t-test. When compared with the Wilcoxon signed-rank test, the emotional performance after listen¬ing was consistent with the paired sample t-test. When all the residents listened to the music, there were significant differences by the Chi-square test in the measure of emotional ratio per person per second. In particular, the increase in the happy emotion was the highest, from 302 (17.09%) to 577 (32.36%). Conclusion: Facial recognition proved that nostalgic old Chinese songs could help promote positive emotional changes in the residents of a long-term care fa¬cility. It is recommended to use nostalgic music therapy to alleviate residents’ emotional distress.