The contents and requirements of risk analysis described in WOAH Terrestrial Animal Health Code were introduced in the paper，considering the provisions concerning biosafety defined in Specifications for the Management of Specified Disease Free Zones published in China and the author's practical experience learned during the construction of farm biosafety systems，the main gaps available in current biosafety systems in China were summarized，specific practices of the system construction based on risk analysis and main measures were proposed，which could guide farms to construct a scientific and systematic biosafety system，thus to improve their level of biosafety，and to scientifically prevent and control major animal diseases.