Objective To analyze the pharmacological mechanism of Shenling Baizhu powder in the treatment of cancer cachexia based on the network pharmacological method and provide a reference for the clinical application of classical traditional Chinese medicine(TCM) prescriptions. Methods Through TCMSP and BATMAN-TCM databases, the main chemical components and their targets of the TCM prescription of Shenling Baizhu powder were obtained, and the active components of the TCM were screened according to ADME. The main targets of cancer cachexia were obtained through OMIM, Genecards, Disgenet and DRUGBANK databases, and protein interaction analysis was conducted using String platform to build a PPI network. The “drug-active ingredient-target” network of Shenling Baizhu powder was constructed by Cytoscape 3.7.2 software, and then the biological processes and pathways involved were analyzed by using Metascape platform. Finally, molecular docking verification was conducted by Discovery Studio. Results The core active ingredients of Shenling Baizhu powder in the treatment of cancer cachexia were quercetin, kaempferol, pyrolignous acid, stigmasterol, luteolin, β-sitosterol, etc. The core targets were AKT1, TP53, TNF, IL-6, MAPK3, CASP3, JUN, CTNNB1, HIF1A, EGFR, etc. The molecular docking test also showed that the top 10 active ingredients, such as pyrolignous acid, stigmasterol and β-sitosterol, had good binding activities with most of the target sites. The biological pathway of Shenling Baizhu powder in treating cancer cachexia wss mainly to regulate tumor related pathway, metabolism related pathway, inflammatory factors and appetite related pathway. Conclusion This study preliminarily revealed the mechanism of action of Shenling Baizhu powder in treating cancer cachexia with multi components, multi targets and multi pathways, which provided a basis for the clinical development and utilization of Shenling Baizhu powder.