This work was focused for studying the effect of ablation time on the producing ZnO nanoparticles by Liquid –Phase Pulsed Lase Ablation (LP-PLA) of Zn metal plate in the aqueous environment of cetyl trimethyl ammonium bromide (CTAB) with molarity (10-2 M) using Q-Switched Nd:YAG pulsed laser has wavelength= 1064 nm, Rep. rate= 10 Hz, Pulse duration =6 ns and laser energy 170 mJ. The effect of ablation time on the optical and structure of ZnO was studied is characterized by UV-visible absorption. UV-visible absorption spectrum has four peaks at 219, 232,242,249 nm for ablation time (5, 10, 15, and 20 min) respectively, our results show that UV–visible spectra show a blue shift in the presence of CTAB with decrease the ablation time and blue shift indicated to get smaller size of nanoparticles. The blue shift in the absorption edge indicates the quantum confinement property of nanoparticles. Also FTIR transmittance spectra of ZnO2 nanoparticles prepared in these states show a characteristic ZnO absorption at 435–445cm−1.