Objective To evaluate the efficacy of thoracic cavity perfusion with cisplatin combined with mannan peptide in nasopharyngeal carcinoma patients with malignant pleural effusion.Methods 47 cases of nasopharyngeal carcinoma patients with malignant pleural effusion with a median age of 50 years old (41-70 years old) were enrolled.Pleural effusion occurred at 38.5 months on average after diagnosis,unilateral effusion was seen in 45 patients (95.7 ％),bilateral effusion was seen in 2 patients (4.2 ％).Cisplatin combined with mannan peptide was administered through pleural puncture by PICC center vein pipe after drainage.Data of survival complications and response to the treatment were reviewed.Results 17 patients (36.1％) had a complete remission (CR),21 patients (44.6 ％) had partial remission (PR),and the total remission rate (CR+ PR) was 80.9 ％.The median survival time was 10.5 months.Patients with pleural fluid pH ≥ 7.2,glucose ≥ 60 mg/L,and lactic dehydrogenase (LDH) ＜ 600 U/L showed association with good efficacy,the efficacy rates were 85.0 ％ (34/40),86.5 ％ (32/37),89.5 ％ (34/38),the median survival time were 11.5,12.0,12.5 months.Pleural fluid pH ＜ 7.2,glucose ＜ 60 mg/L,and LDH ≥ 600 U/L showed association with poor efficacy,the efficacy rates were 42.8 ％ (3/7),50.0 ％ (5/10),44.4 ％ (4/9),the median survival time were 6.5,6.5,6.0 months (P ＜ 0.05).The curative effect of the patients with bone metastasis and (or) pulmonary metastasis without liver metastasis was more similar with that of the patients with liver metastases [(47.0 ％ (16/34) vs 57.1％ (4/7),x2 =0.01,P =0.29].But median survival time had significant difference (11.0 vs 6.0 months,P =0.02).The Cox multi-factor analysis confirmed that the LDH value of effusion was an independent factor as prognosis evaluation.Major side effects of the treatment included fever,chest pain,nausea and vomiting.Conclusion Thoracic cavity perfusion using cisplatin combined with mannan peptide is effective in the treatment of malignant pleural effusion in nasopharyngeal carcinoma patients with pleural effusion,with relatively low toxicity.LDH value is a predictive factor for survival.The patients with liver metastases appeare poor median survival time.