Cancer cachexia is a kind of major complication of various malignant tumors and is characterized by skeletal muscle atrophy adipose tissue degeneration systemic inflammation and various metabolic abnormalities contribute to functional impairment. CT and MRI are capable of qualitatively and quantitatively measuring muscle area muscle density and muscle fat content. Utilizing advanced imaging techniques we assessed skeletal muscle area skeletal muscle index lateral and axial psoas major muscle thickness indices along with other relevant parameters in patients. This comprehensive evaluation aims to provide a more precise and objective assessment of sarcopenia and related conditions facilitating the identification of malignant fluid occurrence and progression stages thereby enabling the formulation of tailored nutritional treatment plans for specific phases. In this paper we review the application and research progress of CT and MRI in the assessment of nutritional status and diagnosis of cancer cachexia in patients with tumors and actively carry out nutritional therapy in patients with nutritional risk or early stage of cancer cachexia to delay the development and improve the clinical outcome of patients.