Abstract: The perforation diameter, perforation ratio, thickness, and cavity depth are the key parameters affecting the sound absorption of micro-perforated panels (MPP). Understanding the effects of these parameters is critical for the optimal design of MPP-based acoustic structures. Existing studies often focus on single-variable analysis or first-order local sensitivity methods, which are insufficient to quantify the relative importance of each parameter. To address this limitation, this study develops a global sensitivity analysis model based on classical MPP acoustic theory and the Sobol' method. The model quantifies first-order, second-order, and total sensitivity indices, thereby revealing the coupling mechanisms among MPP parameters. The analysis results are validated through both numerical simulations and experimental measurements. The findings indicate that below 1000 Hz, diameter and perforation ratio dominate the absorption performance, whereas above 1000 Hz, cavity depth becomes the primary influencing factor, with panel thickness having minimal effect. Across the entire analysis spectrum, strong coupling effects are observed between cavity depth and the other two parameters (diameter and perforation ratio), while a moderate coupling exists between diameter and perforation ratio. This work identifies the dominant parameters and their interaction mechanisms governing MPP acoustic behavior, providing a theoretical foundation and practical guidance for the design of high-performance MPP sound absorbers.