In order to explore the signal networks in which Mopos5 might involve and study the molecular mechanism, cDNA library was screened by using yeast two-hybrid system, and six interaction proteins were obtained. According to bioinformatics prediction and relevant research papers, these candidate interaction proteins were likely to participate in various biological processes, including cytoskeleton morphogenesis, cell movement, cell division, cell ageing and death, maintenance of mitochondrial function, defense response to environmental stress, material and energy metabolism and signal transduction. Further analysis of the biological functions of these interaction proteins and their interaction mechanisms with Mopos5 will be of great significances to make out the signal networks in which Mopos5 might involve and even its molecular regulation mechanisms of colonization and expansion of M. oryzae in rice tissues.