Finite-difference time-domain (FDTD) methods often require smaller spatial discrete steps when calculating the nonlocal properties of metal nanostructures, which brings difficulties to the calculation when the model size is large. However, due to the introduction of longitudinal wave vector, the hydrodynamic model describing the properties of the metal nonlocal property is inconvenient for the calculation of semi-analytical methods such as the transfer matrix method (TMM). Therefore, a method combining FDTD and TMM to solve the absorptivity of nano-metal nonlocal thin films is proposed in this paper. The reflection coefficient and transmission coefficient of the metal are obtained by the FDTD method, and the equivalent dielectric constant of the nonlocal metal is obtained by inversion. Substitute the equivalent permittivity and model parameters into the TMM, and the electromagnetic properties of the complete structure are calculated. The results show that this method can solve the problem of insufficient memory caused by small grid of FDTD and the computational complexity caused by longitudinal wave vector in TMM, and calculations of reflectivity, transmittance, and absorptivity of layered nanostructures can be performed quickly.