An optical storage medium, a method for preparing an optical storage medium, and a system are provided. In this application, the optical storage medium includes a substrate and at least one data layer, the data layer includes a recording layer and a spacer layer, the recording layer is located on the spacer layer, and the data layer is located above the substrate. The recording layer may store data, the recording layer includes an area in which a phase change material is distributed and an area in which no phase change material is distributed, and the two different areas may indicate different data.