Abstract: Nanostructure gallium phosphate was fabricated using laser-induced etching (LIE) process, and the characteristic dimensions were determined with phonon confinement model. The laser was also used for spectroscopic investigations. It was found that the surface phonon frequency depends on the nanocrystalline size, shape and dielectric constant of the surrounding medium, and the broadening Raman line was caused by the size distribution, which was dependent on the etching parameters. The temperature dependent Raman scattering of porous and bulk GaP were compared. The experimental and theoretical results indicated that there was a higher degree of anharmonicity existed in the porous than in the bulk. The anharmonic constants were found to be highly size dependent and increased with decreasing dimensions. The phonon lifetimes decreased with increasing temperatures independent, but both decreasing with decreasing of nanocrystals size...