Circulating antigen and antibody were detected by CAg-dot-ELISA & CAb-ELISA respectively on the clinically confirmed patients of paragonimiasis, people in paragonimus endemic area, cases with early infection of P. westermani, and cases with other parasitic infections. Circulating antigen was detected in 29 out of 70 cases with paragonimiasis with a sensitivity of 41.5%. The rate of cross reaction in cases with clonorchiasis sinensis and schistosomiasis was 25% (5/20) and 20% (4/20), respectively, and it was negative in 60 cases with other parasitic infections and healthy subjects, with an overall specificity of 93.6%. Specific antibody was detected in 67 of 70 cases with paragonimiasis with a sensitivity of 95.7%. The cross reaction rate in cases of clonorchiasis sinensis and schistosomiasis was 25% (5/20) and 20% (4/20), but negative in 60 cases with other parasitic infections and healthy subjects, with a specificity of 92.1%. 220 persons from paragonimus endemic area were all negative in antigen detection and 7 (3.2%) showed antibody positive. Dot-ELISA for circulating antigen detection may be helpful in diagnosing early infection of P. westermani.