Magnaporthe oryzae is an economically important heterothallic ascomycete which causes rice blast, the most destructive rice disease worldwide. To the present, sexual generation of the fungus has been relatively less investigated. In the present work, Guy-11 and 2539, two M. oryzae strains in opposite mating types, were cross cultured on six deferent substrates to induce the sexual generation. The strains produced ascocarps on all of the substrates tested, however, the number, forming time and ripeness degree of the ascocarps varied largely with the producing substrates, among which oatmeal agar(OMA) gave the optimum value. In order to better detect the structures of sexual generation, the asci and ascospores were stained with Fluorescent Brightener and Nile red, and examined using a fluorescence microscopy. Under the fluorescence microscope, the cell walls were stained bright blue by Fluorescent Brightener, which greatly improved the visibility of asci and ascospores. Numbers of asci were found in mature ascocarps, with eight ascospores in each ascus, and an ascospore usually has four cells. Meanwhile, the ascospores can be stained bright orangey-red by Nile red, indicating they are rich in lipids. These findings showed that the fluorescence staining is an effective method to observe the structure of sexual generation in M. oryzae.