Morphological characteristics of the parthenogentic egg of Daphnia （ Ctenodaphnia ） carinata during the embryonic development were studied. At 26℃, the embryonic development took 31 h, including 11 h for the egg stage, 8 h for the long embryo stage, 9 h for the double compound eyes stage and 3 h for the single compound eye stage. Each stage was divided into several sub-stages according to the characteristics during the embryonic development. Therefore, the embryonic development could be divided into eight stages, each of which would be described in detail. At the egg stage, the egg was just spawned from the female＇s ovary, then began to grow up quickly and its inner appearance changed gradually from translucent to transparent, Seven hours later distinct vitelline granules occurred in the egg. At the long embryo stage, the embryo became elongated anteroposteriorly, The egg membrane was cast off. The vitelline granules extended into the cephalic region and all rudiments formed. At the double compound eyes stage, the embryo further elongated with a distinct head, Two pink patches and a brown dot were observed in the head which represented the paired eyes and the oceellus, respectively. The limb rudiments could be seen on the ventral margin of the embryo. At the single compound eye stage, the embryo reached maximum elongation with the eyes becoming dark in color and paired eyes finally fused. The development of the alimentary canal was complete. Trunk appendages became distinct. The juveniles then emerged from the brood pouch. The composition and content of proteins and amino acids during the embryonic development were also measured and analyzed. The results showed the content of soluble proteins decreased during the embryonic development even though it slightly increased at the long embryo stage. The composition of soluble protein changed from the big molecular weight to small molecular weight. Seventeen amino acids during the embryonic development were measured, including 7 essential acids, 8 non-essential acids and 2 semi-essential acids. The content of amino acids decreased during the embryonic development, but slightly increased at the long embryo stage. The Glu content was the highest of all amino acids and the Leu content was the highest of 7 essential acids. The content of proteins and amino acids decreased at the egg stage, but increased at the long embryo stage, then decreased gradually at the double compound eyes stage and single compound eye stage. This changing pattern of the content of proteins and amino acids correlated well with the morphological characteristics during the embryonic development. Based on the morphological characteristics and content and cunaposition of proteins and amino acids during the embryonic development in Daphnia （ Ctenodaphnia ） carinata, it is concluded that the proteins and amino acids were the main nourishment materials during the embryonic development, which not only were used to build the embryonic tissues and organs, but also provided the energy for developing embryo.