African swine fever (ASF) is a devastating disease caused by African swine fever virus (ASFV), characterized by acute feature, high fever, high mortality and other characteristics. ASF mainly outbreaks in African, Eastern Europe countries, Russia and Caucasus region. At present, there are no vaccine available and effective control strategies against ASFV spread, therefore, ASF has a serious impact on the pig industry in the affected countries. The major target cells of the virus are swine reticuloendothelial cells and monocyte-macrophage cells. ASFV can result in apoptosis and affect the host's immune system, and then show the characteristics of the corresponding disease. ASFV has the characteristics of large genome, more genotype and more variability. In this paper, the molecular etiology and pathogenesis of ASFV are reviewed, so as to provide theoretical basis for prevention and control of ASF.