Abstract: Traditional split look-up tables (S-LUT) technology is modified and redesigned to generate computer generated hologram (CGH) with higher computation efficiency without increasing storage space. Two main aspects are involved in the proposed method:(1) The content of original vertical modulation factor look-up tables is changed to record the contribution of space points at same Y coordinate to every row pixels of the holographic plane. With the new look-up tables the number of online CGH computation is greatly reduced and the implementation of CUDA(compute unified device architecture) parallel computation is simplified as well. (2) Phase iteration technology is introduced into the generation of look-up tables offline by substituting addition and subtraction for time-consuming square, square root operation. As a result, the generation efficiency of offline look-up tables is significantly improved. Experiment on generating CGH with two kinds of 3D point clouds shows that, the time for the generation of look-up tables offline in the proposed algorithm is saved about 1-1.5 times, compared to original algorithm, without increasing storage. In addition, the time for the generation of CGH online with new look-up tables is save at least about 15% and parallelization can be easily implemented as well. The proposed algorithm turn out to be valuable for 3D display based on digital holography technology.