There are many reasons why alpha-fetoprotein is lowered and then raised after liver cancer surgery, common ones are recurrence of liver cancer, metastasis of liver cancer, viral hepatitis and so on. 1. Recurrence of liver cancer: the recurrence rate of liver cancer is high after surgery. After complete remission of surgery, regular review and close follow-up should be conducted. If the alpha-fetoprotein gradually rises, one should be alert to the possibility of recurrence of liver cancer. 2. Liver cancer metastasis: if liver cancer cells have metastasized to other parts of the body before surgery, or if the surgery cannot completely remove the primary lesion and cause metastasis such as lung metastasis, the alpha-fetoprotein may be lowered and then elevated again. 3. Viral hepatitis: if viral hepatitis occurs after surgery, it can lead to elevation of alpha-fetoprotein, which is mostly temporary. Generally, mild hepatitis can have mild increase, while severe hepatitis can have obvious increase of alpha-fetoprotein. There may be other reasons such as teratoma, etc. It is recommended to improve the examination to clarify the cause and standardize the treatment.