COVID-19 epidemic bring a great threat to human physical and mental health. This study aimed to investigate the effectiveness of an online mindfulness platform in improving mental status. Patients from a regional hospital were randomly divided into the experimental and control groups. The experimental group received online mindfulness interventions, and control group received general health education. There were no significant differences in the stress or depression scores between the two groups (P > 0.05). Intervention group had significantly lower anxiety scores than control group at fourth and eighth weeks (P<0.001). There was no significant difference in the emotion change over time in control group (P > 0.05). The anxiety in the intervention group was significantly improved at the 4th and 8th weeks (P<0.05). Moreover, the stress and depression in the intervention group were significantly improved at the 8th week (P<0.05). Online mindfulness intervention can effectively improve emotional status.