Autophagy is a ubiquitous degradative pathway for the bulk degradation of eukaryotic macromolecules and organelles in eukaryotic cells (Klionsky, 2005; Levine and Klionsky, 2004). Previously, the role of autophagy in turgor generation in plant pathogenic fungi was unknown. Currently, autophagy is confirmed as an important pathway for turgor accumulation in the appressorium (the tips of the invasive hyphae; Liu et al., 2007b) using a technique of targeted gene replacement, deleting the genes that code for Magnaporthe oryzae homologs of yeast autophagy-related (ATG) genes ATG2, ATG4, ATG5, ATG8, ATG9, and ATG18 (Liu et al., 2007a). All of these null mutants fail to breach the cuticle of the host. This chapter will first look at some methodologies to analyze the functions of autophagy-related gene products at the biological, cellular, and molecular level in this model plant pathogenic fungi, and then provide some research evidence of the role of autophagy in the promotion of the formation of the infection structure and pathogenicity to point out some significant areas for further research in this field.