Abstract：The occurrence of nosocomial infection in patients with malignant tumors is closely related to the decrease of immune function. The deficiency of healthy qi is the core pathogenesis of nosocomial infection in patients with malignant tumors，and the exuberant pathogenic qi is the direct external cause. In the process of using Chinese medicine to prevent and treat nosocomial infection，it is better to reinforce healthy qi and dispel pathogen. In clinical practice， it is not only necessary to use internal application of Chinese medicine decoction and external treatment of Chinese medicine to prevent and control nosocomial infection in patients with malignant tumors， but also to consider the aspects of diet conditioning， emotional care and air elimination management.