BACKGROUND: Respiratory therapists (RTs) play important roles in providing ventilator support to patients in hospitals. They are on the front line in respiratory cases and work with physicians to help patients survive. However, questions remain regarding whether the mental health conditions at work are protected and secured for RTs. This study aimed to explore the risk factors of mental illness for RTs and to design an app to allow individual RTs to seek assistance at an earlier stage. METHODS: A total of 642 RTs from 107 two-tiered hospitals in Taiwan were randomly selected to complete a 44-item, 5-category questionnaire regarding emotional labor and mental health in 2019. Exploratory factor analysis, the Rasch model, descriptive statistics, the nonparametric Mann-Whitney U test, the Kruskal-Wallis test for unpaired t test, and one-way analysis of variance were performed to examine the demographic characteristics and emotional labor and mental health factors that influence RTs' mental health. An app was then designed to evaluate their mental health status. RESULTS: A total of 352 questionnaires were eligible, with a return rate of 54.8% (352 of 642). About 62.8% came from medical centers and 37.2% from regional hospitals. There were 311 (88.4%) women and 41 (11.6%) men, with a mean 6 SD age of 37 6 9.5 y. Six construct factors were extracted from the responses. The overall reliability of the emotional labor and mental health questionnaire for each subscale beyond 0.70 was evident based on internal consistency and stability in the data. Four risk factors (ie, basic emotional expression, superficial emotional control, emotional diversity extent, and weekly work hours) influenced RT mental health. All findings were applied to design an app for RTs to evaluate their mental health at work. CONCLUSIONS: Four risk factors were verified to influence RT mental health. An app was developed to detect their mental health and allow them to seek assistance at an earlier stage.