Zishi township of Jiangling city is located in the canal area inside embankment,a heavy endemic area of schistosomiasis japonica in Hubei province. The population and cattle preva-lence was 29.5% and 66.7% respectively in 1992. There are 66 canals and it covered a total area of 300000m2. 97.0% of the canals and 99.3% of the total area had snail inhabitants, and 7.6% of the snails distributed in canal was infected which covered 18.3% of the total area. The snails were mainly distributed in the main canal and their branches. The rate of snail distribution was 45.2% and 39.8% respectively. Cattle was pastured all year round in this area. Examination of scattered cattle feces and water revealed that the major factor of water contamination was scattered cattle feces. It explained why the infection rate of snail was high and the distribution of infected snail was extensive and how the major high rise area inside embankment was formed.