To address the issue of uneven pressure distribution in the abrasive flow field within the inner hole of components with a large depth/diameter ratio, an adaptive control strategy for regulating flow field pressure difference is proposed in this paper. The strategy was based on the effects of pressure fluctuations at the abrasive flow inlet and outlet on pressure distribution patterns and pressure changes within the inner hole flow field, as derived from numerical simulations. An adaptive control fixture was also designed, enabling dynamic adjustments to the fixture gap, which significantly reduced the pressure difference in the flow field. Experimental results demonstrated that the surface texture uniformity of the inner hole was greatly improved after adaptive control. The non-uniformity in surface roughness after control was 59.1% lower compared to pre-control conditions, indicating improved machining consistency. Furthermore, the maximum reduction in surface roughness increased from 1.146 μm to 1.844 μm, and processing efficiency was notably enhanced.