ObjectiveThis study aimed to compare the efficiency of these two combined surgeries [prolapse and hemorrhoids (PPH) combined with the external hemorrhoidectomy and inferior internal hemorrhoid ligation; tissue selecting technique with mega-window stapler (TST-MS) combined with anal canal epithelial preservation operation]. MethodsThis is a single-center, evaluator-blinded randomized controlled trial (RCT). A total of 204 participants were randomly divided into the two groups. The anal function, reoccurrence, intraoperative variables, and operative complications were assessed. The measurement data were compared by paired t test and rank sum test. Chi-squared or Fisher's exact test was used for count data and rank sum test for ranked data. To assess differences within each group in different time points, the repeated-measures analysis of variance was conducted. ResultsTST-MS combined with anal canal epithelial preservation operation had lower Wexner score of anal incontinence (Z = 3.062, P = 0.002), higher patients’ satisfaction degree (t = 7.32, P < 0.001), less residual skin tags (χ2 = 18.141, P < 0.001), longer operative time (Z = −2.281, P = 0.023), and bigger volume of excised rectal mucosa (t = 2.35, P = 0.020). There was no significant difference between the two groups in the anal canal circumference, recurrence, intraoperative blood loss, weight of excised rectal mucosa, anal pain, bleeding, urinary retention, anal edge edema, and anatomical anal stenosis (all P > 0.05). ConclusionsTST-MS combined with anal canal epithelial preservation operation showed better clinical efficiency in the treatment of prolapsed hemorrhoids. Trial registrationThis study has been registered in Chinese Clinical Trial Registry (ChiCTR2000038533)