Electrocardiographic sign was studied for the evaluation of the state of Corpulmonale in coal workers' pneumoconiosis who were admitted and dead as complication of CWP in Don-ghae hospital, Fourty-eight cases were gatherpd. The prevalence rate of right axis deviation was 28.3%. p-pulmonale in lead II was 30.4%, R/S< or =1 in V5 was 23.9. But che pulmonary artereal pressure can be increased without the change of ECG. so the elortrocardiugraphical sign should be treated as reference data.