One-step precipitation of Ag nanoparticles in Ag -doped silicate glasses was achieved through a focused picosecond laser with a high repetition rate. Absorption spectra and transmission electron microscopy (TEM) confirmed that metallic Ag nanoparticles were precipitated within glass samples in the laser-written domain. The surface plasmon absorbance fits well with the experimental absorption spectrum. The nonlinear absorption coefficient β is determined to be 2.47 × 10^-14 m/W by fitting the open aperture Z-scan curve, which originated from the intraband transition in the $\mathrm{s}-\mathrm{p}$ Ag band. The formation mechanism of Ag-glass nanocomposites is discussed as well.