In the Fresnel condition, the design and optimization method of binary optical element with multi-focus has been investigated. A one-step optimizing algorithm of tilted multi-focus diffractive optical element is presented by using a tilted image plane in the Fresnel approximation.Based on iterative Fourier transform algorithm(IFTA), not only the higher diffraction efficiency, increased about four percent, but also the instability of distributing at the different focus,namely difFerent tilted angle,are obviously improved by the modified simulated annealing algorithm(SA). Comparison on one-step and multi-step circle algorithm of optimizing multi-focus diffraction element shows both the faster speed and the higher difFraction efficiency for the one-step algorithm.