Abstract: To obtain useful information about the mechanism of the artificial induction of gynogenesis in Haliotis diversicolor, we observed the cytological images of diploid control group, triploid group，haploid gynogenetic group and diploid gynogenetic group during meiosis and first cleavage. After incorporated into the egg cytoplasm, the UV-irradiated sperm nuclei could activate eggs to complete meiosis, and sperm nuclei discondensed gradually, liquefied and expanded. Most sperm nuclei eventually developed into the male pronuclei, just like the normal sperms, except sperm nuclei in a few zygotes kept dense throughout the fertilization process. Dense chromosome body (DCB) was seen at the nuclear area during the prophase of first mitosis, and in the middle of spindle at metaphase of first mitosis. At completion of cytokinesis of first cleavage, the DCB was seen in the cytoplasm of one of the two blastmeres near the cleavage furrow. In the CB-treated group, both sets of female chromosomes hold in cytoplasm for chromosomes segregated as in normal zygote but the cytoplasm division was inhibited, formed two chromatin body and eventually developed into two pronuclei.