A fiber sensor for optical measuring surface scattering characteristics in real time is introduced. The laser with 650 nm, 1 310 nm and 1 550 nm wavelength is taken as the light source to test and analyze the samples with different surface roughness. Experimental results show that measuring non-systematic error can be reduced effectively by using multi-wavelength composite light source laser fiber sensors. And measuring accuracy is improved greatly. Besides, the shorter is the wavelength, the greater is the roughness and scattering status will becomes more complicated.