Objective To investigate the occurrence of sarcopenia in hospitalized patients with malignant tumor analyze the related influencing factors and compare the differences in body composition serological indicators and quality of life between the sarcopenia group and the non-sarcopenia group so as to provide clinical data for improving the prognosis of patients. Method A total of 321 hospitalized patients with malignant tumor were collected and their body composition was measured by multi-frequency bioelectrical impedance analyzer. Sarcopenia was diagnosed according to the Asian Sarcopenia Working Group AWGS diagnostic criteria and divided into sarcopenia group and non-sarcopenia group. Nutritional status was assessed by patient subjective global assessment PGSGA systemic inflammatory response was assessed by improved Glasgow outcome score mGPS and quality of life was assessed by the European Quality of Life Collaboration Group cancer core scale QLQ-C30 . Univariate and multivariate Logistic regression were used to analyze the factors affecting the occurrence of sarcopenia. T test and rank sum test were used to compare the differences of body composition serological indexes and quality of life between the two groups. 0. 05 means the difference is statistically significant. Result In this study 102 patients were diagnosed with sarcopenia with an incidence of 31. 78% . The results showed that there were statistically significant differences in the incidence of sarcopenia among different PG-SGA body mass index BMI mGPS groups P< 0. 05 and BMI was an independent factor affecting the incidence of sarcopenia patients with body weight and hemoglobin albumin triglyceride were significantly lower than those without sarcopenia patients while extracellular moisture ratio was higher than those without sarcopenia. The scores of functional domains and symptom domains in quality of life were lower than those in patients without sarcopenia and the scores of constipation and anorexia were higher than those in patients without sarcopenia with statistically significant differences P<0. 05 . Conclusion The incidence of sarcopenia in hospitalized patients with malignant tumors is related to PG-SGA BMI and mGPS and BMI is an independent factor affecting the incidence of sarcopenia. Sarcopenia results in low body weight poor nutritional status high systemic inflammatory response score low phase angle level and poor quality of life.