Abstract: More and more researches about infection structures had been carried out in recent years. Some plant pathogenic fungi could produce infection cushion, appressorium and haustorium to finish infection processes, and their formation and development were very important to plant diseases occurring. Appressorium and associated melanin were critical to penetration, and their formation was controlled by genes, also influenced by such environmental factors as plant surface structures, temperature and pH. Haustorium was not only the organ for nutrient uptakes, but also the area for information exchange between plants and fungi. Extrahaustorial membrane(EHM) was from plant plasma membrane(PM), but their structure and function were different. The interaction between plants and fungi directly led to the ultrastructural changes of haustorium. Research of infection structures and their infection mechanism is significant to prevent and cure the plant diseases in theory and practice.