Abstract: A research group composing of 7 units to assess the diagnostic value of conventional COPT and its relevant improved methods under the same condition, was organized by the diagnosis Group of the National Schistosomiasis Research Committee, in Changshu City, Jiangsu, in 1983. Indirect hemagglutinatiori(IHA) was used as a control means. Sera of 82 cases of Schistosomiasis japonica having positive stool examination, 51 cases of Schistosomiasis japonica after being cured and having negative stool examination, 51 healthy individuals, 5 cases of clonorchiasis and 4 cases of paragonimiasis, were tested, by double-blindness method. The conventional and improved COPT made on parasitologicajly confirmed cases presented a positive rate of 65.9-85.2 %. The diagnostic effect of enzyme-linked COPT and immunofluorescence COPT appeared to be no higher than that of conventional COPT using lyophilized ova of Schistosoma japonicum. The false positive rate tested for the healthy persons was 2.0-33.3%, that of conventional COPT with lyophilized ova was 2.0-7.8%. The results obtained from the conventional COPT after 72 hours incubation (69.5-84.2%) Were higher than those for 48 hours (65.9-73.2%). In contrast, positive and false positive rates of IHA were 91.5% and 3.9%, respectively, the cross reaction of the patients with paragonimiasis being higher than that of COPT.