Abstract: Meishan pig, one of the Chinese Taihu pig breeds, is well known all over the world for the high prolificacy. The recent research progress in the physiological structure and hereditary factors affecting the high litter size of Meishan pig was summarized in the article. The role of the uterus and placenta on the high litter size, and QTL fine mapping affecting the high farrowing performance, the association of polymorphisms of the major genes with high litter size, and the effect of early embryonic development function on high prolificacy were described. Furthermore, how to investigate the causes of high litter size at the genome level was discussed, so as to understand the molecular genetic mechanism of high prolificacy in Meishan pig.