Hemorrhoids are among the most common and frequently encountered chronic anorectal diseases in anorectal surgery. They are venous clusters formed by congestion, expansion, and flexion of the venous plexus in the lower part of the rectum. Mixed hemorrhoids bleed easily and recurrently, and this can result in severe anemia. Hence, they may have a negative effect on the health of the patient and surgical treatment is required. Milligan-Morgan hemorrhoidectomy has been widely used since 1937 for the treatment of grade III and IV hemorrhoids. However, most patients experience different degrees of postoperative pain that may cause anxiety. To assess the factors influencing pain scores and quality of life (QoL) in patients with mixed hemorrhoids post-surgery. The clinical data of patients with mixed hemorrhoids who underwent Milligan-Morgan hemorrhoidectomy were collected retrospectively. The basic characteristics of the enrolled patients with mixed hemorrhoids were recorded, and based on the Goligher clinical grading system, the hemorrhoids were classified as grades III or IV. The endpoint of this study was the disappearance of pain in all patients. Quantitative data were presented as mean ± SD, such as age, pain score, and QoL score. Student's t-test was used to compare the groups. A total of 164 patients were enrolled. The distribution of the visual analog scale pain scores of all patients at 3, 7, 14 and 28 d after surgery showed that post-surgery pain was significantly reduced with the passage of time. Fourteen days after the operation, the pain had completely disappeared in some patients. Twenty-eight days after the surgery, none of the patients experienced any pain. Comparing the World Health Organization Quality of Life - BREF self-reporting questionnaire scores of patients between 14 and 28 d after surgery, we observed that the quality-of-life scores of the patients post-surgery had significantly improved. There were six items that were compared at 14- and 28-d post-surgery. The mean QoL score 28 d after surgery (4.79 ± 0.46) was higher than that at 14 d post-surgery (3.79 ± 0.57). The mean health condition score 28 d after surgery (4.80 ± 0.41) was also higher than that at 14 d post-surgery (4.01 ± 0.62). The mean physical health score 28 d after surgery (32.10 ± 2.96) was significantly higher than that at 14 d post-surgery (23.41 ± 2.85). The mean psychological health score 28 d after surgery (27.22 ± 1.62) was significantly higher than that at 14 d post-surgery (21.37 ± 1.70). The mean social relations score 28 d after surgery (12.21 ± 1.59) was significantly higher than that at 14 d post-surgery (6.32 ± 1.66). The mean surrounding environment score 28 d after surgery (37.13 ± 2.88) was significantly higher than that at 14 d post-surgery (28.42 ± 2.86). The differences in quality-of-life scores at day 14 and day 28 post-surgery were observed to be statistically significant (P < 0.001). Milligan-Morgan hemorrhoidectomy can significantly improve the postoperative QoL of patients. Age, sex, and the number of surgical resections were important factors influencing Milligan-Morgan hemorrhoidectomy.