Abstract: The multi-component quasi-bivariate variational mode decomposition technique is applied to decompose the turbulent boundary layer velocity field acquired by direct numerical simulation. By observing the instantaneous flow field at various cases from low to medium Reynolds number (Re_τ=400~1750), the characteristics of the coherent structures corresponding to different modes are qualitatively obtained. By comparing the morphology and inclination angle of the two-point correlation map, the variation of the inclination angle of the coherent structure corresponding to different modes with the normal height is quantitatively compared. The first mode mainly corresponds to large-scale sweep/ejection events, while the second mode corresponds to near-wall streamwise vortex structures. The variation trend of the inclination angle of the coherent structure of the modes with the normal height is weakly dependent on Reynolds number, which indicates that the geometric characteristics of large and small scale structures follow certain similarity within the Reynolds number range studied.