Abstract: In order to select efficient insecticides to control Oncomelania hupensis gredler，the co-toxicity and control effects of emametin benzoate and niclosamide ethanolamine were detected using immersion method in chizhou, anhui province. And the results showed that LC50 of emametin benzoate to Oncomelania hupensis gredler was 0.039 mg/L, when the mass ratios of emametin benzoate and niclosamide ethanolamine were 20:1~1:20, the co-toxicity coefficient(CTC) were more than 120, the CTC was 399.20 when the mass ratio was 1:10. 24% emametin benzoate?niclosamide ethanolamine EC was made and the control efficacy were tested at the ratio of 0.5 ml/m2, 1 ml/m2 and 2 ml/m2, the results showed that 24% emametin benzoate?niclosamide ethanolamine EC have better effects than 70% niclosamide ethanolamine WP and 6% metaldehyde WG, and the control efficacy were 89.14% and 87.23% after 3 and 5 days when it was used 2 ml/m2, respectively. The combination of emametin benzoate and niclosamide ethanolamine can be used to control Oncomelania hupensis gredler effectively.