INTRODUCTION: Programmed death-ligand 1 (PD-L1) blockade is a growing treatment for extensive-stage small cell lung cancer (ES-SCLC). This study evaluates the cost-effectiveness of benmelstobart and anlotinib plus etoposide/carboplatin (EC) compared versus anlotinib plus EC and EC alone for patients with ES-SCLC in China. METHODS: Using a Markov model over 5-year boundary and data from the ETER701 trials, we analyzed quality-adjusted life-years (QALYs), incremental cost-effectiveness ratio (ICER), total cost, incremental net health benefit (INHB) and incremental monetary benefit (INMB). To address uncertainties, we conducted one-way analysis and probabilistic sensitivity analysis (PSA). Scenario analyses were used to evaluate the resilience of our model's findings. RESULTS: The administration of triple therapy for ES-SCLC demonstrated a significant improvement in QALY, with respective gains of 0.26, 0.39, compared with the other two schemes. However, enhanced therapeutic benefit was accompanied by increased costs. And triple therapy showed less cost-effectiveness with ICER of $189797.99 and $149249.24 per QALY respectively when compared with other schemes. Moreover, the analysis revealed an INHB of -1.04, -1.12 QALYs, and the INMB of -39755.48 $, -42819.93 $ respectively. Sensitivity analysis demonstrated that benmelstobart's cost was the main driver of cost-effectiveness. The cost-effectiveness acceptability curve displayed that the likelihood of triple therapy being cost-effective increased from 34.20% to 97.60% when the threshold value for cost per QALY gained varied from $180000 to $240000. The scenario analysis supported these findings. DISCUSSION: Triple therapy was a less cost-effective option for patients with ES-SCLC compared with anlotinib plus EC and EC alone in China.