BACKGROUND: Soft tissue sarcoma (STS) has lacked reliable prognostic indicators. This study evaluates blood-based inflammatory and nutritional indexes to identify good predictors for STS outcomes. These indicators included neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), systemic inflammation response index (SIRI), lymphocyte-to-monocyte ratio (PNI), albumin-to-globulin ratio (AGR), and platelet-to-albumin ratio (PAR). METHODS: A total of 93 were included, and blood indexes were measured preoperatively. Univariate and multivariate regression analyses identified significant predictors, and model performance was assessed using the Akaike Information Criterion (AIC), Bayesian Information Criterion (BIC), Concordance Index (C-index), and Likelihood Ratio Chi-Square (LR_χ2). RESULTS: Univariate analysis indicated that NLR, PLR, LMR, SIRI, AGR, and PAR show potentially significant differences ( CONCLUSION: Preoperative SIRI is a better predictive index compared to NLR, PLR, and LMR. Preoperative SIRI and AGR are independent risk factors for both DFS and OS. The combination index of the SIRI+AGR+Enneking stage provides a more robust prediction of clinical prognosis in STS patients.