Multi-level recording on rewritable phase change optical disk was studied using a simulation and experiments. The possibility of using multi-level reflection effects to increase the storage capacity was considered using a computer simulation software called phase change optical disk design. Optical and thermal simulations were carried out on disks with phase change material GeSbTe to study its performance. Using a suitable disk structure, the mark shapes of various sizes that give rise to multi-level reflection effects were written on the disk and examined. In order to solve the problem of the difference in the absorption between the crystalline and amorphous states, a thermal compensation layer of Sb was used. Simulation and experiment results have shown that the effect of the difference can be significantly reduced by the thermal compensation layer.