The purpose of the study was to evaluate the quality of life (QOL) after open radical prostatectomy (ORP), laparoscopic radical prostatectomy (LRP) and brachytherapy (BT). Methods: A longitudinal, descriptive, comparative design was conducted in southern Taiwan. A total of 49 prostate cancer patients treated with OPR, LRP and BT were recruited in this study. Data were completed at the following five time points: before treatment/baseline and at 1, 2, 3, and 8 months after treatment. The European Organization on Research and Treatment of Cancer quality of life (EORTC QLQ-C30) was used to assess the QOL in functional scales and global health status. The EROCT Prostate Cancer Module (QLQ-RP25) was used to measure the QOL in urinary symptoms. The generalized estimating equation (GEE) was used to analyze the different QOL values after three treatments within 8 months. Results: There were no significant differences in the functional scales and global health status quality of life between the OPR and BT groups. Additionally, there were no significant differences between the LRP and BT groups in the functional scales and global health status. The QOL in urinary symptoms was worse in the ORP group at 1, 2, and 3 months, and it was worse in the LRP group at 1, 2, 3, and 8 months when the reference group was BT with the baseline time point. Conclusion: Prostate cancer patients had similar QOL in functional scales and global health after three treatments. However, urinary symptoms were worse in the ORP and LRP groups of patients than in the BT groups.