Using the technique of cell-egg electrofusion newly developed by Yi Yonglan and coworkers in fish(1988), we have studied several problem in the Developmental Biology of the electrofused eggs between unfertilized eggs of Paramisgurnus dabryanus and embroynic cells of P. dabryanus and Misgurnus anguillicaudatus. 1. Parafin Successive section of cell-fused eggs clearly demonstrats: (1) The connection and fusion of embroynic cells with eggs and the entering of embrothnic cell nuclei to the inner part of the recipient egg. In the cytoplasm of recipient egg, entered donor nuclei can develp to spindles and go on to division. (2) Several nuclei can be seen in one section, and they can all independly develop into cleavage. (3) Fusion of nuclei may happen in recipient egg. At this time, despite the microtube around the nuclei, the chromosome of both nuclei can be clearly seen. The manner of fusion is quite like the fusion of male and female pronuclei in fertilizition. (4) Have seen tripole-spindle and chrosome exclusion in the nuclei division. 2. By tracing the development of embryonic cell-fused eggs, have found many characteristics different from that of fertilized eggs: (1) In the first clevage, 2-7 blastomeres appear simultaneously. They are not the same size and have different cleavaging speed. (2) The development of cell-fused eggs often be arrested at any stage, which decresing the hatching rate. They are obviously influenced by the forming of partial blastuala. (3) The forming of partial blastula is closely related to the acentric entering of several nuclei to the animal pole of the recipient egg, simultaneously 3. From the number of chromosome of middle-gastrula developed from cell-fused egg, we conclude: (1) One egg can receive two kinds of embryonic cell-nuclei, they can both develop, at least to the stage of gastrula. (2) In recipient rgg, fusion of nuclei has occured, they could happen between donor nuclei or between donor nuclei and female nuclei. 2n = 170± and 2n = 120± may demonstrate this phenomena. (3) The exclusion of chromosomes in fused egg is universal.