Multilevel recording, which allows multiple status in each recording pit, is an alternate way to increase the recording density, but need not to directly reduce the spot size by increasing NA (numerical aperture) or reducing λ. The absorption of photochromic material varies with the different optical writing energy, which can be used to realize multilevel data storage. At first, the exposure characteristic of this material as the media of multilevel storage is studied, and the mathematical model of multilevel storage using this material has been achieved. The nonlinear relation between absorption and exposure energy is reflected in the model, which supports to optimize the write strategy of photochromic multilevel data storage. In the results of 4-level and 8-level static multilevel storage experiments, each level of signal amplitude varies obviously without overlap, which proves the possibility of applying this material to multilevel data storage. The capacity of optical disk will be improved by double or treble if this multilevel technology is implemented into practical optical disk storage.