Abstract: 70 ewes of Duolang Sheep were selected and divided into two groups.After artificial insemination,60 ewes in test group were mated and 10 ewes in control group were dismated.Using platelet counting method,early pregnancy diagnosis was made on 60 mating sheep.The results showed that platelet number of pregnant ewes decreased（74±59.98）×109 /L on the 7th day after mating and had extremely significant differences with that of dismating control ewes（P〈0.01）.The detection results showed that 54 ewes were pregnant and 6 ewes were not pregnant.Through clinical pregnancy examination and the comparison of the lambing results,it was found that the pregnancy coincidence rate of pregnant ewes was 92.59%,that of non-pregnant ewes was 83.33% and total coincidence rate was 91.66%.