Abstract: Objective To summarize processes about molecular mechanisms for the tumor cachexia in recent years. Methods Applying the PubMed, the VIP and the CNKI, with "the malignant tumor, cachexia, skeletal muscle atrophy, the molecular mechanism, the ubiquitin proteasome pathway"as key words, for the retrieval of such literature in recent 10 years. Inclusion criteria: ①malignanttumor; ②cachexia; ③ubiquitin proteasome way; ④skeletal muscle atrophy, according to the standard income the references below. Results In the cachexia, the molecular mechanisms are more complex, mainly including the ubiquitin-proteasome pathway, the regulation pathway of pro-inflammatory cytokines, neuroendocrine pathway and other ways. The study of ubiquitin proteasome pathway research is clear, with proteasomes participation like E1, E2, E3; The regulation pathway of pro-inflammatory cytokines mainly includes the NF-κB pathway, P38β MAPK pathway and muscle inhibin/activin pathway; Neuroendocrine way is mainly glucocorticoids effect, with inhibiting protein synthesis by cutting mTOR, damaging the starting phase of the messenger RNA translation which influences on the protein synthesis and involves the Akt pathway. Conclusions There is correlation among the regulating mechanisms, including with the association of E3 enzymes the most. At the same time, study of the molecular mechanisms of the concrete in the regulation and control and the other way is on the way and the relationships among them may be the breakthrough points.