The interfacial bonding contact state is one of the key factors in determining the integrity of asphalt pavement multilayered composite structure, and the mechanical response of each structural layer will be affected by the interfacial contact state significantly. The non-destructive testing falling weight deflectormeter (FWD) was utilized to study on the identification asphalt pavement interfacial contact state according to deflection basin parameters. Based on the reconstruction and expansion project of Beijing-Shanghai Expressway, a three-dimensional dynamic finite element model of pavement structure was established to analyze the correlation between each FWD deflection basin parameter and the critical stresses of base layer and surface layer under different base layer-surface layer contact states, respectively. The FWD deflection basin index (DD₁=D₀-D₂₀, DD₂=D₂₀ -D₆₀, Where D₀, D₂0 and D₆₀ represent the deflection values of 0, 20, 60 cm from the load center) was constructed to comprehensively reflect the base layer-surface layer stress characteristics, and the regression shows that this index is well on the power relationship with the base-surface interlayer friction coefficient. Considering the fatigue equation of core sample in situ and the finite element simulation results as well, the minimum requirement of friction coefficient between the base-surface layers is derived, which could ensure the life expectancy of asphalt pavement. On this basis, the durability of existing pavement is evaluated, and the results are in consistent with the real engineering case. The proposed method can provide a new approach and theoretical basis for estimating interlayer friction coefficient and evaluating pavement fatigue durability using FWD.