Immunosuppressive drugs are required for life after kidney transplantation, and each immunosuppressive drug has side effects. Too large a dose can bring about many side effects, thus affecting the kidney transplant recipient. If the dose of immunosuppressant is too low, it will lead to insufficient immunosuppression, which will cause acute or chronic rejection. Therefore, grasping the reasonable concentration of immunosuppressant is the key to achieve good results after kidney transplantation. Because of the differences between the Eastern and Western populations, including drug absorption, drug metabolism and the intensity of drug action on the immune system, the Chinese kidney transplant population cannot blindly copy the drug dose and concentration standards of the Western population. Based on more than 20 years of experience, our institute has adopted the strategy of adjusting different immunosuppressive drugs in different periods according to the characteristics of kidney transplantation population in different periods. Of course, the concentration of immunosuppressants will not be a fixed pattern, subject to the experience of transplantation centers, the characteristics of each individual and the degree of tolerance of each person will take the appropriate drug concentration, but the values in the table are relatively efficacious, but relatively few side effects. Each transplant kidney patient should give feedback to the doctor on the side effects after taking the drug, and the doctor will adjust the dose according to your situation to achieve the best individualized treatment dose and concentration to achieve the best results. There are also some uncommon immunosuppressive drugs, such as: imipramine, our recommended dose is 100mg per day in the morning and 100mg per day in the evening, compared with the previous 150mg per day, we believe that increasing the dose will not bring an increase in side effects, but can reduce the occurrence of rejection reactions, with special attention to the combination of imipramine and tacrolimus, the tacrolimus concentration is required to be above 6 within six months after surgery is relatively It is safer. The recommended dose of leflunomide for BK virus-related nephropathy is 50-60 mg per day, and there are usually no significant side effects.