Abstract: X-ray diffraction (XRD) stress measurement has attracted much attention because of its non-destructive nature, high accuracy, and wide applicability. However, the optimization and matching mechanism of its measurement parameters has been lacking for a long time. By constructing a multi-parameter coupling analysis strategy, this study systematically reveals the synergistic mechanism of key parameters such as scanning peak, scanning step, and sin²ψ measuring points on residual stress measurement accuracy for the first time. The experimental results indicate that there is a significant angle effect in the selection of the scanning peak position. When the high-angle diffraction peak of 137.282° is used, the stress calculation error is reduced by 87.64% compared with the conventional angle, which is due to the higher sensitivity of the high-angle 2θ region to the change of crystal plane spacing. The optimization of scanning step size is characterized by two-factor constraints. Although the optimal peak shape fitting degree (R² > 0.92784) can be obtained with the step size of 0.03°, the balance between test efficiency and noise interference needs to be weighed. The minimum data point criterion strategy of sin²ψ method is innovatively established. When the sin²ψ measurement points reach 7, the stress error can be stably controlled within ± 5.7 MPa, which provides a theoretical basis for rapid detection. This study breaks through the traditional single-parameter optimization model and proposes a multi-parameter cooperative optimization strategy, which provides important theoretical support and technical paradigm for the X-ray diffraction residual stress measurement.