A new modified Gerchbery-Saxton (G-S) algorithm based on the technology of the digital image processing to decrease the phase singular spots is presented. The comparisons of the new modified G-S algorithm to the ordinary G-S algorithm are made, and the results show that the new modified G-S algorithm has the ability of making the phase distribution curve sleek and further decreasing. Finally, the phase distribution of the diffractive optical elements needed as the hollow beams are transformed from Gaussian beams is obtained by this algorithm, 8.31% RMS error is achieved and the phase values of about 33.2% of the total pixels are modified which make the curve of phase distribution of the diffractive optical elements sleek for ease of microprocessing.