The temperature in deep carbonate rock formations is high, and the acid-rock reactions are primarily governed by H+ mass transfer. In order to accurately characterize the kinetic parameters of acid-rock reactions in deep carbonate formations and to elucidate the flow and distribution patterns of acid fluids within fractures, this study combines numerical simulations with mathematical calculations to investigate the variations in wall dissolution characteristics under different influencing factors. The primary conclusions drawn from the study are as follows: 1. The distribution pattern of rock dissolution rates under varying fracture widths and flow velocities closely resembles the morphology of dissolution height, with the dissolution height on the fracture surfaces approximately following a normal distribution, primarily concentrated around 15–16 μm. 2. With different acid fluid viscosities, the H+  mass transfer coefficient exhibits an exponential decrease as viscosity increases. The average dissolution height decreases from 17.4 μm for a viscosity of 10 mPa·s to 3 μm for a viscosity of 200 mPa·s. 3. At varying acid fluid concentrations, the H+  mass transfer coefficient shows a linear increase with concentration. The distribution of rock dissolution rates within acid-fractured fractures and the dissolution height exhibit significant differences. For every 5% increase in acid concentration, the dissolution height increases by 3–5 μm. 4. Using grey relational analysis, the study identified the relative importance of factors influencing the morphology of acid dissolution on the wall surface controlled by mass transfer: fracture width > flow velocity > concentration > viscosity.