In May 2019，an outbreak of African swine fever（ASF）was confirmed in Huinong District of Shizuishan City，Ningxia Hui Autonomous Region. In order to trace the sources of the disease and analyze any risks of spreading，an epidemiological investigation was carried out by means of field and follow-up investigation，discussion，sampling testing and others. It was investigated that the outbreak was more likely caused by cross-infection among workers and vehicles that used to transport live pigs，the epidemic might also be introduced by stray dogs and wastes or sundries，however，the risk of epidemic spreading was low. Therefore，it was suggested that the knowledge on ASF prevention and control should be further publicized by local government to make farms/households promote their bio-safety level，the cleaning and disinfection of staff，materials and vehicles should be strengthened，the management of trans-regional movement of live pigs and pig products，inspection and quarantine at the place of origin，vehicle registration as well as the cleaning and disinfection of related premises and vehicles should be standardized. Upon the above investigation，some references were provided for prevention and control of ASF in Ningxia.