Gastric cancer is a common gastrointestinal malignant tumor. In my clinic, I encountered many gastric cancer patients who had recurrence and metastasis within one or two years after surgery, and some patients did not have timely review, resulting in serious recurrence and metastasis. adjuvant therapy. The key to reduce the recurrence of gastric cancer patients after surgery and how many years they can live after surgery is the treatment method chosen. As long as gastric cancer is treated with correct adjuvant therapy after surgery, early gastric cancer is completely possible to be cured, and even patients in the middle and late stages can have late recurrence and small recurrence through adjuvant therapy, as well as realize the hope of long-term survival with tumor. In addition to the toxic side effects such as nausea, vomiting, anorexia, hair loss, large ulcers and poor mental health, radiotherapy will also bring great toxic side effects, mainly on liver and kidney function and suppression of bone marrow cells and white blood cells, resulting in extreme decrease of immunity, and even the number of immune cells and white blood cells will drop drastically, making it impossible to continue treatment. In addition to killing cancer cells, radiotherapy also kills a large number of patients’ own immune cells and normal tissue cells, making patients’ immunity low and unable to resist cancer cells from invading patients’ immune system again, which, to some extent, also gives cancer cells the opportunity to invade patients again, creating certain conditions for metastasis and recurrence. Clinically, it is recommended that post-operative gastric cancer patients can combine radiotherapy and bio-immunotherapy treatment to achieve the most ideal treatment effect. DC-CIK cell therapy in biological therapy enhances the body’s defense ability against cancer by improving the body’s immune function. That is, by inducing the body’s active immunity and the secondary immunity to readjust the balance between the disrupted organism and cancer, the immune function of cancer patients can be restored to kill tumor cells in the body to achieve the purpose of controlling tumor growth and prolonging the survival of patients. Biological therapy for early stage gastric cancer after surgery can further kill the tiny lesions invisible during surgery and cancer cells free in blood, consolidate the efficacy of surgery, help patients recover and enhance the function of immune system after surgery while effectively inhibit the proliferation of cancer cells, and prevent the recurrence and metastasis of tumor through the regulation of immune mechanism. Combining DC-CIK cell therapy with post-operative radiotherapy can continue to kill residual cancer cells, consolidate the efficacy of radiotherapy and enhance patients’ active anti-cancer ability by regulating their own immune mechanism, which can inhibit the proliferation of cancer cells for a long time and effectively prevent tumor recurrence and metastasis after radiotherapy. DC-CIK cell-activated immune anti-cancer technology takes out lymphocytes and single nuclei cells from peripheral blood of tumor patients, stimulates them by activation, and co-cultures them with patented reagents under sterile laboratory conditions, and finally obtains activated lymphocytes with the ability to specifically kill patients’ own tumor cells, called DC-CIK cells (chain-activated immune cells) to obtain specific tumor-killing function. After transfusion back into the body, they can kill tumor cells in the body, thus achieving the purpose of killing tumor cells. Therefore, DC-CIK biological therapy is effective and can be used after gastric cancer surgery to effectively prevent disease recurrence and prolong the life of gastric cancer patients. As an adjuvant treatment after surgery, biological therapy is very effective in preventing recurrence of gastric cancer after surgery. It also plays a certain role in helping patients to cure the disease. The survey found that the survival period of using biological therapy in postoperative adjuvant treatment is much higher than that of not using biological therapy. The author would like to remind gastric cancer patients that biologic therapy is the first choice of anti-tumor treatment for advanced and severe patients, as well as patients who are too old and poor to adapt to surgery and radiotherapy, which can help patients reduce pain and prolong life.