Abstract: Investigating the changes and the underlying causes of turbulence movement in boundary layer during the growth of squall lines is crucial for enhancing the understanding of squall line mechanisms. 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 significant accumulation of environmental instability energy. In the development stage, a steep gradient of surface equivalent potential temperature (θ_se) is observed, surface cyclogenesis intensifies, triggering 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. The squall line moves southeast and merges with dispersed convection. On the maturation stage, the mid-level dry and cold air influx strengthening subsidence and forming a cold pool at the surface. As the middle of the squall line breaks, it enters the stage of extinction. (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 decreases to a minimum during nighttime weakening of the squall line. (3) During the formation stage, strong turbulence facilitates substantial latent heat flux upwards, creating a highly unstable environment; by 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 convective initiation stage, ground vortices result in wind shear being 2-3 times the negative buoyancy term, with terrain uplift contributing to increased TKE. After the formation of squall line, the cold pool reduces TKE, while in the maturation stage, the squall line moves into a complex terrain region where both positive wind shear and negative buoyancy terms peak, 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.