Both mucinous cystadenoma of the appendix and intestinal schistosomiasis are rare lesions. We report a rare case of simultaneous giant mucinous cystadenoma of the appendix and intestinal schistosomiasis. A 64-year-old man from China presented with a one-year history of pain in the right lower quadrant of the abdomen. There were no other pertinent historical findings, other than schistosomiasis. Imaging showed a large, tubular, mesenteric cystic structure extending downwards from the inferior wall of the cecum. Right hemicolectomy was performed for the appendiceal tumor. The final pathological diagnosis was mucinous cystadenoma with calcified Schistosome eggs within the mucosa and submucosa of the appendix, small intestine, colon, and lymph nodes. We deduced that the pathogenesis of appendiceal mucinous cystadenoma in our case was Schistosome eggs causing luminal obstruction, finally resulting in intraluminal accumulation of mucoid material. Postoperatively, the patient recovered well.