Abstract: The wide application of synchronized oestruses and laparoscopical intrauterine insemination was of great significance for changing the production pattern and economic structure of mutton sheep industry and procreating 1.5-2 ewes lambs per year. The synchronized oestrues and laparoscopical intrauterine insemination were made on local hybrid sheep in Inner Mongolia in the breeding and anoestrous seasons. The results showed that the oestrns percentage of ewes in breeding and anoestrous seasons were all over 93%, without significant difference. Some of hybrid ewes with small-tail sheep bloodline were observed by laparoscopical surgery on the 6th day after synchronized oestrus to check the number of the corpus luteum. The average ovulation rates were 2.45 and 1.69 per sheep respectively. The pregnancy rate of mutton sheep by laparoscopical intrauterine insemination was significantly higher than that by conventional artificial insemination.