The research sought an investigation of the effect of multi-scale coherent eddy structures on scale- similar LES (large eddy simulation) sub-grid model of turbulence flow. The main focus of the study examined the valid scale range of LES scale-similar sub-grid model, as well as its evolution in normal-wall direction across turbulent boundary layer. Time sequence signals of longitudinal velocity component at different normal-wall positions in turbulent boundary layer are measured by IFA300 constant temperature anemometer and hot-wire probe with sampling resolution higher than the frequency that corresponds to the smallest time scale of turbulence. Multi-scale coherent eddy structures are extracted from turbulent fluctuating velocity signals by locally-averaged velocity structure function and conditional sampling method. Velocity fluctuating signals, including or excluding coherent eddy structures, are separated respectively. A comparsion of scale-correlation factors with and without multi-scale coherent eddy structures was performed. The mechanism of kinetic and momentum transfer in turbulence was revealed utilizing the concept of multi-scale coherent eddy structure. There is a scale range where scale similarity is valid. The scale where LES scale-similar sub-grid model is valid must be smaller than the maximum energetic scale.