Pork containing lean meat is generally bright red, with bright color, very thin fat, full and prominent gluteal muscles, loose lean fiber and a lot of "sweat" oozing from the meat surface. Abdominal fat, perirenal fat and intermuscular fat decreased significantly. Heart, liver, spleen and lung atrophy, especially spleen atrophy is more serious. Capillaries in the inguinal fat layer on both sides of the carcass are densely distributed and even congested. According to the test paper, normal fresh meat is mostly neutral or weakly alkaline. After slaughter 1 hour, the pH is 6.2 ~ 6.3, and after cooling for more than 6 hours under natural conditions, the pH is 5.6 ~ 6.0. However, the pork containing "Clenbuterol" is acidic, and its pH value is obviously lower than the normal range.