This paper deals with the study of the. early development of Rana nigrwna-culaia, the most common species of frogs in this country. It includes a description of the external forms, internal anatomy, a normal developmental time table at 18℃ of the embryos and a comparism with those of other species of Rana. In addition, a series of photographical records of the developing embryos was taken as a suppliment. Beginning with the artificial fertilization of the completion of the operculum of the tadpole 307 hours are needed. On the basis of the morphological and the physiological characteristics of the embryos, the whole course of development is devided into 25 stages, and in certain aspects, the development of this frog closely resembles to that of Rana pipiens. This paper deals with the study of the. Early development of Rana nigrwna-culaia, the most common species of frogs in this country. It includes a description of the external forms, internal anatomy, a normal developmental time table at 18 ° C of the embryos and a comparism with those of other species of Rana. In addition, a series of photograph records of the developing embryos was taken as a suppliment. Beginning with the artificial fertilization of the completion of the operculum of the tadpole 307 hours are needed. On the basis of the morphological and the physiological characteristics of the embryos, the whole course of development is devided into 25 stages, and in certain aspects, the development of this frog closely resembles to that of Rana pipiens.