A novel low coherence interferometer (LCI) is proposed for obtaining higher resolution in optical coherence tomography. Three reference mirrors are used in this LCI to generate reference lights. The output signal of this LCI is a superposition of interference of signal light with three reference lights. Through adjusting relative intensities of reference lights, the width of the axial point spread function for the LCI can be reduced, then the resolution will be improved. The influences of fluctuations of wavelength and mirror separation on the resolution are investigated. It is expected that this new approach may provide an effective and useful technique for optical measurement.