The effects of scattering on interference spectral signal and depth resolution in Fourier domain optical coherence tomography are researched. The results obtained from theoretical analysis and simulation show that scattering of sample can change the measured spectral shape, which shifts to longer wavelength, and decrease the depth resolution of image. When the value of scattering coefficient is larger and the position in sample is deeper, the spectral signal will shift more seriously and the depth resolution will decrease more. The depth resolution can be improved by using the corresponding correction function.