The influence of nanosecond laser surface modification on the femtosecond laser-induced damage of 800 nm Ta2O5/SiO2 dielectric film is investigated in this paper. Surface modification of samples is performed by Raster-scanning with scanning mode of 1-on-1 and scanning velocities timed such that there is a beam overlap at 70% of the peak fluence by 5 Hz-1064 nm-12 ns NdYAG fundamental lasers. Femtosecond laser damage of samples is carried out by 1 kHz-800 nm-135 fs Ti: sapphire laser system with 1-on-1 mode test. The result indicates the femtosecond laser-induced damage thresholds (LIDTs) of all the samples with various modification fluence steps are reduced by about 20%, which seems to be closely related with the contribution of the microscopic electronic defects (native or laser-induced trapping states) in the band gap.