Abstract: In order to shorten the estrus interval of the spring postpartum ewes, to achieve two years of three producing sheep or three years five,and promote young ewe normal estrus, the estrus synchronization test was divided into 3 batches, compared estrus induction effect from two factors of different sources of CIDR and treatments on Small-taied Han sheep and the young ewes. The results showed that estrus rate（93.75%） and pregnancy rate（100.00%） in the group of the New Zealand CIDR+PMSG were higher than the other groups, followed by domestic CIDR group（85.19%, 86.96%） and domestic CIDR+PMSG group（81.48%, 90.91%）. The Australia CIDR（13 d） group on postpartum ewes is better than domestic CIDR（13 d） group, but the conception rate（87.88%） lower than the domestic group（100.00%）, considering from the aspects of estrus and pregnancy rate,domestic CIDR（13 d）+PMSG group was better. domestic CIDR（12 d）+PMSG group of young ewes estrus rate was the highest（100.00%） in 72 h, followed by the New Zealand CIDR group（52.00%） and the domestic CIDR（13 d）+PMSG group（51.22%）,while the interestrus conception rate from high to low are the domestic CIDR（13 d）+PMSG group（90.48%）,the New Zealand CIDR group（84.62%） and domestic CIDR（12 d）+PMSG group（69.75%）. It was concluded that the best estrus and conception rate of postpartum two months ewes is the used of domestic CIDR（13 d）+PMSG group, the domestic CIDR （12 d）+PMSG group induced by young ewes estrus rate was the highest.

Key words: postpartum ewes, young ewes, estrus synchronization, CIDR, PMSG, estrus rate, pregnancy rate