The reason why gastric tube should be inserted after gastric cancer surgery is mainly for gastrointestinal decompression and feeding. 1. Gastrointestinal decompression: after gastric cancer surgery, the pressure in the abdominal cavity may be high, at this time, gastric tube can be used for gastrointestinal decompression treatment, which can reduce gastrointestinal pressure by suctioning out the excess liquid and gas in the stomach through negative pressure. 2. The need of eating: after gastric cancer surgery, you can not eat normally, but you need to supplement nutrients to promote recovery after surgery. After gastric tube is left in place, you can eat through gastric tube, and you can use wall-breaking machine to break food into pieces and inject them into the body through gastric tube, so that the nutrients of the body can be replenished, and the recovery can be fast. However, attention should be paid to small amount and several times when injecting food. Keeping gastric tube after gastric cancer surgery is a thing that has more advantages than disadvantages, and family members must understand it.