Ab initio quantum mechanics, classical molecular dynamics and two-temperature model integrated multiscale simulation is carried out to study the effects of film thickness on the femtosecond laser spallation and ablation of silver film. At an interval of 130.7296 nm, five silver films with increasing thickness from 392.1888 nm to 915.1072 nm are simulated. The simulation results show that film thickness has close correlation with the Kelvin degree of heating of the laser irradiated silver films, which further affects the laser spallation and ablation.