Gastric cancer is one of the four major malignant tumors, it’s a kind of malignant tumor with a high mortality rate. Patients with gastric cancer often do not get an early diagnosis, and when they are clinically diagnosed with gastric cancer, usually they already missed the best time for treatment, which causes surgery and other treatment methods fail to give full play to their effect. The detection of human respiratory gases based on electronic nose (e-nose) technology is a new emerging rapid non-invasive diagnostic method. By detecting the exhaled gases of human oral cavity and analyzing the volatile gases in the exhaled gases, it analyzes the content and concentration of typical and warning volatile gases of gastric cancer in the exhaled volatile gases, provides early warning of the occurrence of gastric cancer and analyzes and diagnoses the stage of gastric cancer. This paper combines with the current e-nose technology to design an e-nose respiratory gas detection system for gastric cancer detection, aiming to provide a fast and accurate method for early prevention and diagnosis of gastric cancer.