Phytophthora infestans, which is responsible for potato and tomato late blight disease, belongs to Oomycetes, Peronosporales, Pythiaceae and genus of Phytophthora. Most research focus on P. infestans because it is destructive to potato production. Firstly, in this review, late blight symptoms caused by P. infestans, disease occurrence characteristics and epidemiology were illustrated, then the inheritance of sexual reproduction occurrence and variation of population structure with coexistence of various mating types, were also summarized. Since P. infestans genome sequenced in 2009, characteristics of genomics in various species among genus of Phytophthora were compared, and the research progress of effector clonging and mitochondrial genome were also introduced. Finally, the review demonstrated two significant technologies in functional genomics, high density genetic linkage mapping and genome-wide association study (GWAS), which were convenient for functional genes searching. This review can help to better understand the research highlight and further breakthroughs of P. infestans, which may provide a reference to further analysis on functional gene and pathogenic mechanism of P. infestans, and it is important to develop chemical control targets and epidemic trend forecasting.