Abstract: Objective To explore the clinical characteristics of occupational pneumoconiosis complicated with pleural effusion，accurately understand the risk factors of pneumoconiosis complicated with pleural effusion and poor survival. Methods The clinical data of 30 pneumoconiosis patients with pleural effusion（observation group） and 30 patients without pleural effusion（control group） in the Yunnan First People's Hospital from May 2018 to October 2020 were collected，and the clinical characteristics of the two groups were compared. Results There were statistically significant differences between the observation group and the control group in the clinical features of the highest body temperature[（38.11±0.82）℃]，chest pain（73.3%），dyspnea（53.3%），pneumoconiosis stage Ⅱ and Ⅲ（80.0%），CT pleural effusion（90.0%），and biochemical indexes such as C-reactive protein [66.98（20.18，127.22）mg/dL]，D-Dimer[1.78（1.12，5.74）mg/L]，CD4⁺T cells[325.00（201.05，382.99）cells/μL]，blood oxygen saturation（0.72%），antithrombin Ⅲ[（107.95±12.01）%]，prothrombin time[（13.86±1.56）s]，plasma fibrinogen[（4.74±1.98）g/L]，vital capacity[（2.89±0.56）L]，forced expiratory volume in the first second（FEV）[（2.19±0.45）L] and FEV/forced vital capacity[（48.15±5.02）%]（all P<0.05）. The multivariate logistic regression analysis showed that C-reactive protein，antithrombin Ⅲ，prothrombin time，chest pain，dyspnea，and pneumoconiosis stages were the main clinical features for predicting pleural effusion. Conclusion The pneumoconiosis complicated with pleural effusion indicates more serious disease classification and deterioration trend，which should be given more attention and more timely and accurate diagnosis and treatment.

Key words: Pneumoconiosis, Complicated with pleural effusion, Disease classification, Clinical characteristics