Objective: To investigate the diagnostic value of some antibodies in peritoneal fluid of patients with gastric cancer and malignant epithelioid mesothelioma in serous effusion. Methods: One hundred and eighty-two cases of serous effusion were collected at Jilin Cancer Hospital, from July 2012 to July 2016. The expression of GLUT1, CDX2, Villin, calretinin and WT1 was evaluated using SP immunocytochemical technique in peritoneal fluid samples collected from 98 patients with gastric cancer and 74 patients with reactive mesothelial cells. The expression of GLUT1, calretinin and WT1 was also evaluated in serous effusion from 10 patients with mesothelioma. Results: The sensitivity of GLUT1, CDX2 and Villin in adenocarcinoma cells was 91.8%(90/98), 68.4% (67/98) and 88.8%(87/98), respectively. The specificity was 95.9% (71/74), 100.0%(74/74) and 100.0% (74/74), respectively. The sensitivity of calretinin and WT1 for reactive mesothelium was 93.2% (69/74) and 79.7% (59/74), respectively. The specificity was 96.9% (95/98) and 100.0% (98/98), respectively. The sensitivity of GLUT1, calretinin and WT1 for mesothelioma was 9/10, 9/10 and 7/10. The reactivity of GLUT1, CDX2, Villin, calretinin and WT1 showed a significant difference (P<0.01) between adenocarcinoma cells and reactive mesothelium. The reactivity of GLUT1 showed a significant difference (P<0.01) between mesothelioma and reactive mesothelium. Conclusions The optimal combination is a panel of GLUT1, CDX2, Villin, calretinin and WT1 for differential diagnosis between adenocarcinoma cells and reactive mesothelium in peritoneal fluid of patients with gastric cancer. Whereas GLUT1, calretinin and WT1 is the best for differential diagnosis between reactive mesothelium and mesothelioma in serous effusions.