After the instability caused by lattice depth fluctuation is eliminated using power feedback, the effect of the phase fluctuation for a laser propagating through space or other media on the interference contrast of ultracold atoms in an optical lattice is investigated. A man-made and tunable phase noise is introduced by shaking the optical lattice and its effect on atomic interference contrast ratio is measured. It is found that the phase noises with different intensities have different effects on the experimental results. However, the phase noise with a small intensity has a trivial effect on the interference contrast ratio of ultracold atoms. At present, the measurement accuracy of interference contrast ratio cannot fully show the influence of laser phase on the coherent property of a cold atomic system. This means that this kind of optical lattice with a spatial configuration possesses a good robustness in the capture of ultracold atoms. Furthermore, in order to improve the phase stability, a laser phase locking technique is proposed for the optical lattice with a spatial configuration, which can effectively reduce the phase noise in the lattice system and provide a basis for the future high precision measurements by an optical lattice with a spatial configuration.