This thesis studied the healing effects of the Compassionate Samadhi Water Repentance (hereinafter referred to as "Water Repentance") ceremony on the participants. Through the ritual of paying homage to the Buddhas by chanting their names, reflecting and repenting the sins that the participants have committed. The participants were able to see themselves honestly and then forgive themselves wholeheartedly. Thus, it was proven to achieve the healing effect of emotional regulation. This study adopted a single-group pre-test and post-test quasi-experimental design, employing the participants of the Water Repentance Ceremony from the four monasteries in Taiwan. Initially, there were 260 participants in the pre-test, 37 participants were withdrawn as those respondents had not completed the survey for assorted reasons, leaving a total of 223 participants (a recovery rate of 86%). Then they underwent a three-month intervention with only 163 participants completed the intervention program and took the post-test. 12 participants were dropped out in the post-test as they could not be able to finish the questionnaires, leaving a total of 151 participants (a recovery rate of 93%). The assessment tools for the pre-test and post-test are the "Self-Forgiveness Scale" and "Emotion Regulation Strategy Scale." The SPSS 28.0 statistical package is used for descriptive statistics, including independent sample t-test, paired sample t-test, one-way analysis of variance (ANOVA), and Pearson's correlation coefficients. Open-ended questions are also used to supplement the shortcomings of quantitative data analysis. The critical findings of the study are as follows: 1.The process of penance in the Water Repentance ceremony can achieve emotional stability by listening skillfully and mindfully, followed by repeating reflection and contemplating deeply and then applying that knowledge into practice. 2. The study explored the differences between the process of penance and the self-forgiveness in the Water Repentance ceremony. 3.When facing negative emotions, most participants took a positive approach of “self-reflection" to see the ill-effects of the emotion on themselves; some of them tried to work on the problem on their own; others sought support from outside; a proportion of them endeavored to divert their attention from the stressful situation momentarily. Above all, participants agreed that taking part in the Water Repentance ceremony had a positive effect on stabilizing emotions. 4. The Buddhist healing is mainly categorized into short-term and long -term effects. Through the process of hearing the Dharma, they started to contemplate Dharma teachings, and eventually modified their negative behavior in a constructive manner. The analysis of open-ended questions revealed that participants mostly expressed filling with Dharma joy when conveying their physical and mental feelings. Finally, this thesis on the relationship between Buddhism and psychology will be presented with relevant suggestions and future research directions. This study focused solely on the exploration of quantitative results, supplemented by open-ended questions. However, it fell short of accurately addr
