Objective To explore a rapid and easy measure of perishing Schistosoma ova and cercariae by 50％ calcium cyanamide (commercial name Rongbao) at hot spots in Lake Regions,so as to meet the purpose of infection sources control.Methods The fresh positive cattle excrement containing schistosoma ova was collected for experientment.In summer,autumn and winter,cattle excrement was applied by the measures of stiring (SG),surface spraying (SSG) and middle-inside depositing (MDG) with the proportion at 3 g and/or 5 g of Rongbao per 100 g of cattle excrement at hot spots,the control group (CG) was cattle excrement with schistosoma ova without application.After applying Rongbao,the excrement was collected at different times and miracidia were examined by hatching method.For perishing Schistosoma cercaria in infectious water,the proportion of 10 g/m3 Rongbao were sprayed.The sentinel mice surveillance was implemented for infectious water detection before and after spraying.Results In summer,miracidia were not existed after 2 d in SG and SSG,and it was not existed after 3 d in MDG.In autumn,1-5 miracidia were existed after 2 d among 3 groups,and there were no miracidia in SG and SSG after 3 d,except 1-5 micacidia in MDG.In winter,2-3 miracidia were existed after 3 d except SG,no miracidia after 7 d in 3 groups.However,6-10 miracidia were existed in the control group after 7 d in summer,autumn and winter.As to the treatment of infectious water by Rongbao,the infection rate of sentinel mice was 11.11％ before treatment,while there were no infection at 1 d,15 d and 30 d after treatment examined by dissection,meanwhile,died fishes were not founded.Conclusion The 3 kinds of measures all have perishing effect on Schistosoma ova.According to the result for the field use,the suitable proportion and method are 3 g Rongbao per 100 g cattle excrement by SSG in summer.Schistosoma cercaria were perished by spraying Rongbao at the proportion of 10 g/m3 into infectious water.Above of all,the infection source of Schistosoma will be perished when SSG and infectious water spray are implemented at hot spots.