Abstract: The spiral chute is a widely used fluid film gravity separation equipment, and the stability of the sorting fluid significantly impacts mineral sorting. In the spiral chute mineral sorting process, the distance-to-diameter ratio and the diameter are the primary structural factors significantly affecting the flow pattern and fluid stability. Therefore, in this research,computational fluid dynamics (CFD) technology was used to build the sorting flow fields for spiral chutes with varying diameters and distance-to-diameter ratios to examine how the aforementioned parameters affected the sorting fluid’s stability and flow pattern. The results indicated that as the diameter increased, both the film thickness and the surface tangential flow velocity at the outer edge of the spiral groove tended to increase while the percentage of laminar flow region decreases. Furthermore, the peak Reynolds number and Froude number of the fluid rose noticeably, leading to a decline in surface stability and an increased probability of roll waves. As the distance-to-diameter ratio increased, the flow film became thinner at the inner edge and thicker at the outer edge of the groove. There was a significant increase in the tangential flow velocity at the fluid surface in the middle zone, and the proportion of the laminar flow region at the inner edge decreased. Additionally, the Froude value at the inner edge and the middle zone showed relatively great increments, thereby increasing the likelihood of roll waves occurring in these regions.