The shape of trap-pit strongly affects the reflective characters of multi-crystalline silicon (mc-Si) surface. Using Fourier transform, a model how the trap-pit shape affects the textured surface reflectance is investigated, and a simple expression for calculation of the etched surface reflectance is given. The theoretical analysis shows the strong dependence of reflectance on the textured shape and the trap-pit density. It is found that the reflectance is low for the etched surface covered with U-deep trap pit, but it is high for the etched surface full of V-shallow trap-pit. In experiments, mc-Si was textured in the acid solution with different concentration, sample′s surface was scanned by SEM and the reflection spectrum was measured in the 350~1100 nm wavelength range. The experimental results fit the theoretical analysis well.