In order to make the optical disk having good recording/reading performance and long-term stability, the multilayer structure of the phase-change optical disk must be optimized. By using the design software capable of simulating and analyzing the reading process for phase-change optical disk design, a phase-change optical disk structure for the blue laser(405 nm) was designed optically. The relationships between the(multilayer′s) optical parameters(reflectivity and reflectivity contrast) and the film thickness of the structure and the depth of the groove are studied. The optimum structures of the phase-change optical disk are lower ZnS-SiO_2/AgInTeSb/upper ZnS-SiO_2/Al layered structure of 100 nm/10 nm/25 nm/60 nm for land recording and 140 nm/15 nm/30 nm/60 nm for groove recording. The depth of the groove is 50 nm. The simulation results have great instructional effect on the fabrication of the high density blue-ray phase-change optical disk in the future.