Abstract: To investigate the changes and the underlying causes of turbulence movement in the boundary layer during the growth of squall lines, this study uses the Weather Research and Forecasting (WRF) model to simulate a squall line event in South China from May 11 to 12, 2020. Based on the agreement between simulated and observed data, high-resolution model output is used to analyze the boundary layer structure and turbulence flux transportation characteristics of the squall line process, with turbulence kinetic energy (TKE) features analyzed through the turbulence kinetic energy budget equation. The results are as follows. (1) Based on radar echo evolution and observational data, the squall line process is divided into four stages: formation, development, maturation, and dissipation. During the formation stage, there is a significant accumulation of environmental instability energy. In the development stage, a steep gradient of surface equivalent potential temperature (θ_se) is observed. The intensified surface cyclogenesis, triggers the release of instability energy, leading to the growth of the convective monomer merging with the back of the convection cell and an increase in the horizontal scale of the squall line. Then the squall line moves southeast and merges with dispersed convection. During the maturation stage, the mid-level dry and cold air influx strengthens subsidence and forms a cold pool at the surface. As the squall line breaks at the middle part, it enters the stage of dissipation. (2) The boundary layer turbulence during the squall line event is intense, with TKE accumulating during convective initiation and subsequently decreasing. As the squall line merges with dispersed convection and reaches maturity, TKE rapidly increases to an unusually high value. Then it decreases to a minimum during nighttime weakening of the squall line. (3) During the formation stage, strong turbulence facilitates the upward motion of substantial latent heat flux, creating a highly unstable environment. In the maturation stage, the latent heat flux reaches its maximum in the stratiform cloud region behind the squall line with the squall line further intensifying to its peak. (4) TKE variations are primarily influenced by wind shear and buoyancy terms. During the convective initiation stage, ground vortices amplify the wind shear to be 2-3 times the negative buoyancy term, with terrain-induced uplift increasing TKE. After the formation of the squall line, the cold pool reduces TKE. During the maturation stage, the squall line moves into a complex terrain region where both positive wind shear and negative buoyancy terms reach their peaks, with wind shear exceeding buoyancy terms by more than ten times, resulting in an increase of TKE and enhanced turbulence flux transport to its maximum.