A useful assay for epidemiological survey of H. pylori infection was reported, using the urease antigen of H. pylori to detect the anti-urease antibody in sera from 676 patients suffered from gastropathy with ELISA technique, and compared with whole cell antigen. Results showed that the purified urease antigen was better than whole cell antigen. The partially purified urease antigens rapid diagnostic reagent of H. pylori was examined in hospital/institution and compared with whole-cell antigens. Results of sera from 676 H. pylori-positive gastritis and non-ulcer dyspepsia patients being tested showed that specificity and sensitivity of ELISA were 96% and 98% respectively. It seemed to be very useful for epidemiological studies on H. pylori infection. The use of ELISA in the detection of IgG antibodies against H. pylori was also sensitive, specific and rapid in assessing the improvement of both acute and chronic inflammation, cleaning of bacteria and the antibody titers after treatment, so as recognized an ideal diagnostic method.