Abstract: Phreatic evaporation constitutes a critical vertical linkage in the vertical interaction between surface water and groundwater systems. Accurate simulation and quantification of phreatic evaporation processes are of great significance for the assessment and sustainable management of shallow groundwater resources in the Huaibei Plain. This study utilizes observed phreatic evaporation data from the Huaibei Plain, incorporating key measurements from the Wudaogou Hydrological Experimental Station to evaluate the regional characteristics of phreatic evaporation. The applicability of commonly used phreatic evaporation formulas in the Huaibei Plain was systematically evaluated, based on which the Ye Shuiting formula was further optimized. An advanced iterative algorithm was employed, integrating spatially distributed observed groundwater depth data across the plain, to meticulously simulate the historical variation and dynamics of phreatic evaporation processes, particularly focusing on the distinctive lime concretion black soil and yellow fluvo-aquic soil areas. Future projections of precipitation and evaporative capacity derived from five CMIP6 climate models were used as the primary climatic forcing factors. A Long Short-Term Memory (LSTM)-based multi-model ensemble approach was employed to integrate these climate projections. Combined with the phreatic evaporation iterative algorithm and the optimized Ye Shuiting formula, this approach was used to project future trends of phreatic evaporation in the Huaibei Plain under the SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios. The results show that: 1) The Ye Shuiting formula shows high applicability to both lime concretion black soil and yellow fluvo-aquic soil at the Wudaogou Hydrological Experimental Station. The improved Ye Shuiting formula outperforms other empirical formulas in simulating phreatic evaporation in the Huaibei Plain of Anhui Province. The historical annual average phreatic evaporation in the Huaibei Plain follows the order: yellow fluvo-aquic soil area (254.5 mm) > areal average of Huaibei Plain (179.3 mm) > lime concretion black soil area (108.5 mm). Phreatic evaporation in all subregions of the Huaibei Plain exhibited an increasing trend during the historical period. 2) The LSTM-based multi-model ensemble method demonstrates strong capability in reproducing the variations in precipitation and evaporative capacity during the baseline period. Projections indicate that future precipitation and evaporative capacity over the Huaibei Plain under the three emission scenarios exceed historical levels, with the ranking SSP5-8.5 > SSP1-2.6 > SSP2-4.5. Results derived from the phreatic evaporation iterative algorithm show that the amplitude of groundwater depth fluctuations under the three future emission scenarios is smaller than that during the historical period. Specifically, groundwater depths under the SSP1-2.6 and SSP2-4.5 scenarios are lower than those during the historical period, whereas those under SSP5-8.5 exhibit a significant deepening relative to the historical period. 3) The magnitudes of phreatic evaporation variations under the three future emission scenarios exceeds those in the historical period, exhibiting an overall increasing trend. The increase amplification amplitudes and change rates rank from smallest to largest as SSP1-2.6, SSP2-4.5, and SSP5-8.5. Notably, the change rate and associated uncertainty in winter are significantly higher than those in spring, summer, and autumn. The findings have enhanced the calculation accuracy of phreatic evaporation, thereby contributing to the data reference for modeling and projecting phreatic evaporation and water cycle components in the Huaibei Plain.