Objective To determine the accuracy of MOC-31 in the diagnosis of the malignant effusion by meta-analysis. Methods We search the databases of domestic and international. After a systematic review of both English and Chinese literatures，the sensitivity，specificity，positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio accuracy of MOC-31 in the diagnosis of benign and malignant effusion were pooled using random effects models. Summary receiver operating characteristic curves was used to summarize overall test performance. Results Sixteen studies involving 1602 samples were included. The summary estimation for MOC-31 in the diagnosis of benign and malignant effusion was as follows. The sensitivity was 0.90（95％CI：0.88-0.92），specificity 0.98（95％CI：0.96-0.99）， positive likelihood ratio 18.43（95％CI：11.38-29.84）， negative likelihood ratio 0.11（95％CI：0.07-0.17） and diagnostic odds ratio 349.19（95％CI：138.73-878.95）.The crossing point of sensitivity and specificit（Q value）was 0.96. Conclusion MOC-31 determination is a high sensitive，specific and SROC test for the diagnosis of malignant effusion. Measurement of MOC-31 is thus likely to be a useful diagnostic tool for benign and malignant effusion. The results of MOC-31 assays should be interpreted in parallel with clinical findings and results of laboratory examination.