The appressorium is the key structure for the rice blast fungus to infect the host. The initiation and development of appressorium are regulated by cAMP, mitogen-activated protein kinase and Ca2+ signal pathways. And they are also regulated by the protein for host surface recognition, melanin and glycerol generation, autophagy, and the SNARE protein. This paper has reviewed the appressorium initiation and development from the above aspects.