In this paper the beet pulp (BP) before and after of chemical treatment by three solvents was characterized. The examination of the Infra-Red (IR) spectrum of this material before treatment shows the existence of several characteristic peaks of several functional groups of cellulose, hemicellulose and pectin. After treatment of this material with the various solvents, the results obtained show that the treatment of BP by various solvents has a considerable effect on the chemical modification of the structure of this material. The X-ray Diffraction (XRD) results show that this material contains two zones, crystalline zone and amorphous zone. The analysis of the morphology obtained from this material by Scanning Electron Microscopy (SEM), shows that, this material contains compact and ordered zones, and disordered and porous zones, containing of fibers characteristic of hemicelluloses. After treatment by the three solvents, it can be concluded that the treatment with distilled water and ethanol has a considerable effect on the removal of some constituents of the original material. On the other hand, the treatment of the beet pulp with formaldehyde in an acid medium leads to a compact and ordered material.