Abstract: Objective: To investigate the causes and diagnostic treatment of pseudomyxadenoma in peritoneal cavity.Methods: Four cases of pseudomyxadenoma in peritoneal cavity were analyzed retrospectively.Two cases underwent complete tumor resection,and the others underwent cytoreductive surgery.Results: One case was found with myxadenoma secondary to post-appendicectomy,the other three cases with pseudomyxadenoma peritonei secondary to the rupture of ovarian myxadenoma.Two cases died of bowel obstruction and the whole body failure in half a year after operation because of extensive implantation in peritoneal cavity.The other two cases survived well under the treatment of peritoneal chemotherapy.Conclusions: Peritoneal pseudomyxadenoma is a secondary malignant tumor with low degree.It presents in redistribution phenomenon.Prevention is a key point.The suitable treatment is to receive combined therapy,which operation is dominant.