According to the generation mechanism of speckle, utilizing the concept of interference on a pixel point, a speckle suppression method was proposed which can reduce the Speckle Contrast (SC) of the projection image by limiting the phase distribution range in the optical field. The SC formula is derived in the uniform interval phase range for partially developed speckle conditions, showing that when phase distribution rang is limited between 0.6π and 2π, a quasi-oscillatory behavior of SC appears with the change of phase distribution rang; and SC will be falling rapidly with the lessening of phase distribution rang when phase distribution rang is smaller than 0.6π. An ideal simulation model and a real simulation model were established to verify the correctness and feasibility of this method. In the ideal simulation model, the SC can be reduced from 66.44% to 0% as the phase range limitation varying from 2π to 0. In the real simulation model, the actual structure of the optical path was simulated in the laser projection system, there are two diffractive optical elements in the real simulation model, one is for laser shaping, and the other one is for limiting the phase range of optical field, the SC is reduced from 92.78% down to 2.09% in the real simulation model. The proposed approach presents a significant reference with a low power consumption and a stable display architecture for speckle suppression application in holographic display.