Abstract: 120 diseased chicken with coccidiosis in a chicken farm were divided into four group （30 chicken in each group）. Group 1 was positive control group （infected and untreated）and chicken in other three groups were treated with three kinds of anticoccidial drugs （sulfaquinoxaline, dliclazuril and decoquinate）. Another 30 healthy chicken were used as healthy control group. The drug administration lasted five days and 150 chicken were killed and examined on the eighth day. The anticoccidial index （ACI） was calculated to judge the treatment efficacy of drugs against coccidiosis. The results showed that the anticoccidial index of decoquinate was the highest and it was a kind of high-efficacy anticoccidial drug. ACI of dliclazuril was the next and it was a kind of medium- efficacy anticoccidial drug. ACI of sulfaquinoxaline was the lowest and it was a kind of inefficient anticoccidial drug.