Abstract: In this article a definition of hail embryo is proposed, and the possible errors of judgement of the embryo due to the limitation of the method of slice test or of appearance discrimination are discussed. Based on observations of 7 hail-storms on Qinghai plateau in which 269 stones are collected and tested with 1500 photos taken, the author has analyzed different kinds of embryos on the plateau, showing the existence of multi-grain graupel embryo, and proving that hail embryo in the highland is mainly graupel, amounting to 84%,15% of which is multi-grain graupel; and 4% of hail embryo is frozen-drop. The author has also analyzed the crystal size and isotopic deuterium in discussing the condition of the development of the graupel embryo at a temperature of -13℃ to -25℃ within the altitude of 7000 to 9000 meters above sea level. It is found that at a higher level mufti-grain graupel develops quicker than the normal graupel.