Enlargement of mesenteric lymph nodes one year after gastric cancer surgery may be caused by reactive hyperplasia, inflammation and lymph node metastasis. 1. Reactive hyperplasia: The mesenteric lymph nodes can be reactively enlarged due to the stimulation of mesenteric lymph nodes by some lesions, infections or food allergy or food intolerance inside or outside the intestinal tract. 2. Inflammation: the mesenteric lymph nodes are infected by bacteria and viruses, resulting in inflammatory reaction of the mesenteric lymph nodes, or inflammation of the gastrointestinal tract, inflammation of the abdominal tissues or organs, resulting in the enlargement of the mesenteric lymph nodes. 3. Lymph node metastasis: It is difficult to cure gastric cancer by surgery, radiotherapy and other local treatments, and gastric cancer is easy to recur and metastasize to mesenteric lymph nodes after surgery, which may lead to enlarged mesenteric lymph nodes one year after gastric cancer surgery. It is suggested that patients should consult doctor in time, improve relevant examination under doctor’s guidance to make clear diagnosis, and follow doctor’s instruction to carry out scientific and reasonable treatment.