Abstract: Conidia were the major germ cells for the asexual reproduction of filamentous fungi such as Aspergillus and Penicillium. The karyotype of conidia was diverse, and its multinucleated characteristics had many effects on the growth, development and genetic regulation of filamentous fungi. The formation of conidiospore and karyotype variations were regulated by multiple genes. In this paper, the development process of conidia of filamentous fungi and the function of genes related to the regulation of karyotype variations were summarized., in order to provide theoretical basis for the better utilization of filamentous fungi resources and the genetic manipulation of related species.