Objective To explore risk factors for infection after subtotal gastrectomy in patients with gastric cancer, and provide reference for prevention of infection. Methods Clinical data of gastric cancer patients who were admitted to a hospital from July 2010 to June 2014 for subtotal gastrectomy were analyzed retrospectively, related factors for post-operative infection were explored. Results A total of 210 gastric cancer patients who underwent subtotal gastrectomy were enrolled, 36 patients had healthcare-associated infection (HAI) after operation, incidence of HAI was 17.14%, the main HAI were abdominal infection (n=10) and surgical site infection (n=9). Univariate analysis showed that incidence of post-operative infection was higher in gastric cancer patients who were older than 55 years, malnutrition, laparotomy, tumor-nodes-metastasis (TNM) stage Ⅲ-Ⅳ, and bedridden time >4 days after operation (all P<0.05). Logistic regression analysis showed that patients' age >55, malnutrition, and laparotomy were independent risk factors for infection after subtotal gastrectomy (all P<0.05). Conclusion Old age, poor nutritional status, and laparotomy are risk factors for infection after subtotal gastrectomy in patients with gastric cancer, effective prevention and control measures should be formulated according to these factors before and after operation.