Full range optical coherence tomography (OCT) without additional group delay based on spatial carrier frequency is developed. A grating takes place of the mirror in the reference arm of the traditional OCT system and phase difference between adjacent A-scans without additional optical path difference is introduced by using phage modulation. Spatial interferograms is obtained from the detected OCT signal by the transverse Fourier transform and filtering. For filtering signal, an inverse Fourier transform is done. A full range OCT image can be obtained after axial Fourier transform. The theory and the system based on the spatial carrier frequency are introduced. The investigation on the image quality under different modulation frequencies is experimentally conducted. The full range OCT images of mirror and finger are presented.