A method of obtaining a liver food product, the method being for cleaning, detoxifying and cells and tissues preservation of a fresh animal liver, characterized in that comprises the following steps: S1: taking out a whole fresh liver from an animal body quickly and removing gallbladder, with blood vessels in first porta hepatis of the liver being retained when taking out the liver; S2: spreading the liver taken out gently on a clean plane, dissecting the first porta hepatis of the liver quickly and determining portal vein, biliary tract, hepatic artery and upper and lower ends of inferior vena cava, and inserting disinfected medical catheters into blood vessels of the portal vein, the biliary tract and blood vessels of the hepatic artery; S3: perfusing a perfusate of 30°C-35°C into the catheters in the portal vein, the hepatic artery and the biliary tract, the perfusate fully flows into a hepatic sinusoid system through the portal vein and the hepatic artery and fully flows into a biliary system through the biliary tract; wherein, in step S3, the perfusate is a solution of water and salt, and a ratio of the salt to the water is 8.5-9 grams of the salt per thousand milliliters of the water; S4: perfusing the perfusate continuously, macrophages and immune cells containing toxins, blood and harmful substances in the liver are eliminated from the upper and lower ends of the inferior vena cava continuously and bile is flushed out from the biliary tract system; S5: perfusing continuously, until the fresh liver becomes white from blood red, and (a) then taking down the catheters from the portal vein, the biliary tract and the hepatic artery of the liver to complete the vascular perfusion cleaning, detoxification and cells and tissues preservation of the liver or (b) the vascular perfusion cleaning, detoxification and cells and tissues preservation of the liver are completed when the fresh liver becomes white from blood red. S1: taking out a whole fresh liver from an animal body quickly and removing gallbladder, with blood vessels in first porta hepatis of the liver being retained when taking out the liver; S2: spreading the liver taken out gently on a clean plane, dissecting the first porta hepatis of the liver quickly and determining portal vein, biliary tract, hepatic artery and upper and lower ends of inferior vena cava, and inserting disinfected medical catheters into blood vessels of the portal vein, the biliary tract and blood vessels of the hepatic artery; S3: perfusing a perfusate of 30°C-35°C into the catheters in the portal vein, the hepatic artery and the biliary tract, the perfusate fully flows into a hepatic sinusoid system through the portal vein and the hepatic artery and fully flows into a biliary system through the biliary tract; wherein, in step S3, the perfusate is a solution of water and salt, and a ratio of the salt to the water is 8.5-9 grams of the salt per thousand milliliters of the water; S4: perfusing the perfusate continuously, macrophages and immune cells containing toxins, blood and harmful substances in the liver are eliminated from the upper and lower ends of the inferior vena cava continuously and bile is flushed out from the biliary tract system; S5: perfusing continuously, until the fresh liver becomes white from blood red, and (a) then taking down the catheters from the portal vein, the biliary tract and the hepatic artery of the liver to complete the vascular perfusion cleaning, detoxification and cells and tissues preservation of the liver or (b) the vascular perfusion cleaning, detoxification and cells and tissues preservation of the liver are completed when the fresh liver becomes white from blood red.