Backgrounds: With the rapid spread of COVID-19, strict home confinement has been implemented in most parts of Chinese regions. Millions of people were not allowed to leave their homes except for special reasons. Home confinement plays an essential role in curbing pandemic and promoting preventive behaviors, but it may affect individuals’ mental health as well.

Objects: The objective of this study was to explore the psychological impacts of home confinement.

Materials and Methods: We collected more than 150,360 Weibo messages from 5,370 Chinese active users, and then extracted psycho-linguistic features from these messages. Psycho-linguistic analysis was carried out using the 2 (confinement vs. non-confinement) _ 2 (before vs. after confinement) repeated measure analysis of variance (RM ANOVA).

Results: The results showed that the frequency of positive emotion words was remarkably decreased during home confinement [F.1;5368/ = 7.926, p = 0.005, !2 = 0.001]. In high-endemic subgroup, home confinement also reduced the frequency of exclusion words [F.1;3445/ = 4.518, p = 0.034, !2 = 0.001] and inhibition words [F.1;3445/ = 10.154, p = 0.001, !2 = 0.003].

Conclusion: Home confinement caused a decline in the use of positive emotion words. This indicates that home confinement can increase the frequency of negative emotions. The changes of exclusion words and inhibition words in high-endemic areas may be related to the high epidemic threat and the urgent need for social distancing in these areas.