On the basis of optimized laser parameter,the effect of laser ablation parameters on the silver nanoparticles colloid was analysed. Particles size,morphology and absorption spectroscopy of the obtained nanoparticles colloids are obtained by ultraviolet to visible(UV-vis) spectrophotometer and transmission electron microscopy. The average diameter and distribution of the colloids are analyzed by Image-ProPlus software. The results show that the Ag nanoparticles with best characterization are those produced at the repetition rate of 10 Hz and laser fluence of 4.2 J/cm2 by ablating for 7.5 min in the distilled water with SDS,with the least average diameter (D=11.88 nm),the narrowest distribution of particle size (δ=19.6 nm) and more homogeneous morphologies. That effects of experimental conditions on the silver nanoparticles colloid can be explained by explosion and melt inducing aggregation of colloidal particles by self-absorption of laser pulses.