Objective The anti-hemorrhoid efficacy and adhesion of mussel adhesive protein (MAP) was studied and its mechanism evaluated. Methods Croton oil was used to stimulate the anorectal mucosa to establish the model. Forty specific-pathogen-free grade Sprague-Dawley rats were divided into four experimental groups. One hour after model creation, different treatments were applied to each group by rectal administration under anesthesia. General observation was performed on the fourth day. A 1% solution of EBD was injected into the tail vein 30 min before rats were sacrificed. Approximately 8 mm of rectum was cut off and weighed to calculate the anorectal coefficient. Vascular permeability was evaluated by measuring EBD concentrations. Western Blot was used to detect relative protein expression levels of Muc2 and Muc4, and ELISA was used to detect expression of serum tumor necrosis factor ( TNF-α), interleukin ( IL-6), and malonaldehyde (MDA) in rats. Fluorescence imaging of FITC-labeled MAP at different times was compared and observed by fluorescence microscopy. Results General observations revealed that MAP could reduce the redness, edema, mucosal secretion, and exudation in the rectal area of rats. Anorectal coefficient result suggested that MAP could reduce the degree of rectal swelling (P < 0. 01), and EBD contents suggested that MAP could reduce local vascular permeability (P< 0. 01). Relative expression levels of mucins Muc2 and Muc4 were increased (P< 0. 05), whereas expression levels of serum TNF-α, IL-6, and MDA were decreased ( P< 0. 01). Fluorescence imaging indicated that FITC-MAP could maintain good adhesion and stability in the rectum. Conclusions MAP could increase the expression of mucosal mucin, inhibit inflammation, repair the mucosal barrier, promote mucosal healing, and improve the symptoms of hemorrhoids in a rat model, which can provide a reliable basis for preclinical research of hemorrhoids drugs.