Pulse-width dependence of optical coating damages at 1053 nm laser wavelength is studied. Quarterwave-thick single layer films of high-index materials of A1²O³, ZrO² and TiO², and low-index materials of MgF² and SiO² were tested. Damage thresholds of the MgF² and SiO² films follow the square root dependence on the pulse-width τ (√τ scaling) over the pulse widths of 0.35-90 ns. Although the damage thresholds of the A1²O³, ZrO² and TiO² films followed the √τ scaling from 0.35 to 1 ns, they become independent of the pulse-width for the pulse-widths longer than 6 ns. That is, the pulse-width dependence of the damage threshold is determined by the absorption property of the coating layer, which controls the damage mechanism.