Abstract:In 1989-1991, the material of Prunus mume (Xiyeqing cv.) for the embryological study was collected in Nanjing area. The peak of the differentiation period ofcarpellary primodium was on the first decade of Oct. During the last decade of Dec., the ovules primodia formed. In the fol-lowing year, starting from the last decade of Feb. to the early March, the embryo sac drifted to-wards maturation. The development of embryo sac conforms to Polygonum type. Two semianatropous ovules were contained in the ovary, but usually only one could develop into a seed. The ovule is crassinucellar with nucellar cap, and an obturator arises near its micropyle. Af-ter 2-3 days of pollination, pollen tubes passed through transmitting tissue and entered into the ovary. About 5 days after pollination, most of the embryo sacs were already double fertilized, the free nuclei of endosperm appeared 8 days after pollination, and the proembryo differentiation init-iated about thirteen after pollination. The process of embryo development belongs to Asterad type.