Waterflooding has long been a widely used tertiary recovery method to enhance oil production in most oil reservoirs. Traditionally, the design of this method did not account for the composition of the injected water. However, over recent decades, the potential benefits of injecting low salinity water (LSW) instead of high salinity water (HSW) have gained significant attention. In the oil and gas industry, LSW core flooding experiments have become a standard approach for analyzing the interaction between injected LSW and HSW in sandstone reservoirs. These experiments offer valuable insights into the reaction mechanisms at play. Numerical simulations of LSW core flooding provide even deeper understanding, revealing how various ions in the injected water and FW impact oil recovery under different conditions. The primary aim of this paper is to simulate the LSWF process in sandstone plug cores, refining the accuracy of the model to closely match experimental results and extending its applicability. Additionally, the study seeks to verify the key mechanisms behind LSWF in sandstone reservoirs. The simulation results closely aligned with the experimental data, with a relative error of less than 5%. Moreover, the simulations confirmed the validity of the Multicomponent Ion Exchange mechanism and refuted the Fine Migration mechanism through detailed analysis of ion concentrations in the aqueous phase and mineral composition. This high level of accuracy demonstrates the reliability of the model and its potential for effective application in future scale-up processes.