We investigated the haze and the surface roughness of textured Si substrates etched by $XeF_2$ etching system with the etching parameters of $XeF_2$ pressure, etching time, and etching cycle. Here the haze was obtained as a function of wavelength from the measured reflectance. The haze of textured Si substrates was strongly affected by the etching parameter of etching cycle. The surface roughness of textured Si substrates was calculated with the haze and the scalar scattering theory at the wavelength of 800 nm. Then, the surface roughness was compared with that measured by atomic force microscope. The surce roughness obtained by two methods was changed with the similar tendency n terms of $XeF_2$ etching conditions.