Based on a cohort of 490 patients with decompensated liver cirrhosis due to hepatitis C, this article constructs and verifies a machine learning death risk prediction model with random forest as the core. The study finds that ten indicators, including direct bilirubin, cholinesterase, alpha-fetoprotein, prothrombin time, total bilirubin, high-density lipoprotein cholesterol, alkaline phosphatase, immunoglobulin E (IgE), CA19-9, and CA125, have the most predictive value; the AUC of the random forest model reaches 0.811 (reaching 0.926 in some analyses), significantly better than the traditional Child-Pugh (AUC=0.758) and MELD (AUC=0.639) scores, with higher stability and excellent sensitivity under low false positives. The study also reveals that non-traditional indicators such as IgE and CA125 are closely related to inflammation, tumor microenvironment, and metabolic disorders, expanding the biological understanding of liver cirrhosis progression.