The mechanism of coherent stimulated light scattering and the characteristics of the surface ripple in the laser interaction with materials is described. Experimental research on the surface ripple with Si material irradiated by pulsed laser, is carried out with 1.06 μm laser wave length, 15 mJ energy, 2 mm spot diameter, about 10 ns pulse width and Brewster angle incidence. The surface ripple′s modality of the laser-induced Si material is measured by optical microscope and atomic microscope. A set of liner ripple structure with parallel, equal spaces is found at the surface of silicon material after pulsed laser irradiation under a little higher laser intensity than damage threshold. If this ripple phenomena is related to sound wave velocity in material, the ripple period could be well explained according to the sound wave velocity and pulse duration, and thermal stress is a main role in the formation of surface ripple.