Cellulose is produced over tens of billions of tons every year in the world. It is one of the most abundant natural polymer resources. Compared with petroleum-based polymers, cellulose has very excellent features, such as renewability, wide availability, low-cost, biocompatibility, biodegradability and carbon-neutrality, etc. So it is considered as a competitive candidate to replace petroleum-based polymer materials. Unfortunately, natural cellulose molecules are always close packed by inter-/intra-hydrogen bonds, and are very difficult to be dissolved in common solvent. In recent years, it is found that urea can improve the solubility and stability of cellulose in aqueous alkali solution. The dissolution mechanism and role of urea have not been understood clearly, so we propose to use Sandals to study the cellulose dissolution mechanism and the role of urea in the process.