Objective According to global leadership initiative on malnutrition (GLIM) diagnostic criteria, two procedures of direct diagnosis and nutritional risk screening before diagnosis were used to diagnose malnutrition in hospitalized patients with malignant tumors, and to discuss the consistency of the two procedures. Methods From January to December 2020, 385 patients with malignant tumors were randomly selected from the first people′s Hospital of Yibin. The incidence of malnutrition was assessed by direct GLIM criteria diagnosis (one⁃step) and nutritional risk screening and then diagnosis (two⁃step), finally the consistency of the two procedures in diagnosing malnutrition was compared. Results ① The incidence of nutritional risk in patients with malignant tumors was 51.4% (198/385), and there were significant differences in the incidence of nutritional risk among different age groups, tumor types and tumor stages (P<0.05). ② Among the five phenotypes of GLIM criteria, the incidence of weight loss, low body mass index (BMI), muscle loss, eating loss or digestive dysfunction and the burden of disease or inflammation was 44.4% (171/385), 17.9% (69/385), 42.3% (163/385), 76.1% (293/385), and 38.7% (149/385) respectively. ③ According to the GLIM criteria, the positive rate of malnutrition diagnosed by“one−step”and "two⁃step" was 51.4% (198/385) and 42.6% (164/385) respectively. No matter "one⁃step" or "two⁃step", the positive rate of malnutrition had significant differences in age, tumor type and tumor stage. The older the age, the higher the incidence of malnutrition, digestive system tumor was higher than other tumors, and the higher the tumor stage, the higher the incidence was(P<0.05). ④ 127 cases of malnutrition were diagnosed by the two procedures. There was a good consistency between "one⁃step" and "two⁃step" in the diagnosis of malnutrition with kappa value 0.44. Conclusion The incidence of malnutrition and nutritional risk in patients with malignant tumors is high. The "two⁃step" method recommended by GLIM is more suitable for nutritional diagnosis and treatment.