We present the first, to our knowledge, metasurface holographic display method with exceptional fidelity and minimal edge noise, based on highly uniform flat-top light generated by a digital micromirror device (DMD). Based on the error-diffusion algorithm and iterative refinement process, the amplitude distribution of the initial Gaussian light was dynamically closed-loop modulated, and the standard difference of the intensity of the 3 mm diameter center flat-top beam was reduced to less than 3.4%. The holographic image generated by a flat-top beam illuminated metasurface using this method exhibited a reduction in the brightness coefficient of variation (CV) from 0.82 to 0.58 and a reduction in the contrast difference (CD) of an image pixel intensity from 240 to 160. This method can efficiently improve the quality and uniformity of flat-top light, developing a new perspective for high resolution and fidelity metasurface holographic display by modulating a light source.